From f409e8effd3bda88ecd39a9a54730bdc3dbedba9 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Mon, 24 Aug 2026 16:30:24 +0000
Subject: [PATCH 1/2] Add Excel format option to the invoicing report

The invoice recipient report was PDF only, so the figures could not
be filtered, corrected or re-summed without retyping them. A format
dropdown in the export form now offers Excel alongside the PDF.

The workbook mirrors the PDF layout with one worksheet per recipient,
but writes amounts as real numbers and every totals row as a SUM
formula. Each formula also carries its computed result as a cached
value: tools that do not evaluate formulas, such as pandas reading
via openpyxl, otherwise see those cells as empty. Recipient names are
user-controlled, so worksheet names are sanitised against exceljs's
rules: forbidden characters, the 31-char cap, case-insensitive
collisions, the reserved name "History", and edge quotes exceljs
rejects. Non-finite amounts are written as empty cells rather than
NaN, which Excel would otherwise report as a corrupt workbook.

Data loading and recipient grouping move to InvoicesReportData, which
both report formats extend, so the two always show the same rows in
the same order. InvoicesReport.spec.ts is unchanged and covers the
refactor.

Generation failures now propagate instead of being swallowed: the
saga clears the in-progress flag in a finally block (fixing the same
gap in the pre-existing PDF path), so a failed report cannot leave
the form stuck disabled with nothing shown.

exceljs is reached through a dynamic import kept in its own module,
so its ~1MB bundle lands in a separate chunk that is only fetched
when a report is generated, and is excluded from the service worker's
precache manifest so it isn't downloaded on install either.

InvoicesExcelReport.ts is at 100% statement/branch/function/line
coverage; the wiring in InvoicesReportData.collect(), the saga's
format branching, and the format parameter's round trip through the
container and form are each covered directly rather than simulated.
---
 package-lock.json                             | 1009 +++++++++++++++--
 package.json                                  |    2 +
 .../ReportForm/FormatDropdown.spec.tsx        |   45 +
 src/components/ReportForm/FormatDropdown.tsx  |   57 +
 src/components/ReportForm/ReportForm.spec.tsx |   40 +
 src/components/ReportForm/ReportForm.tsx      |   18 +
 .../InvoicesReportFormContainer.tsx           |   10 +-
 src/containers/containers.spec.tsx            |   51 +-
 src/locales/de.json                           |    8 +-
 src/locales/en.json                           |    8 +-
 src/modules/reports/sagas.spec.ts             |  131 +++
 src/modules/reports/sagas.ts                  |   30 +-
 src/util/InvoicesExcelReport.spec.ts          |  533 +++++++++
 src/util/InvoicesExcelReport.ts               |  360 ++++++
 src/util/InvoicesReport.ts                    |  160 +--
 src/util/InvoicesReportData.spec.ts           |  107 ++
 src/util/InvoicesReportData.ts                |  199 ++++
 src/util/downloadBlob.spec.ts                 |   58 +
 src/util/downloadBlob.ts                      |   21 +
 src/util/loadExcelJs.spec.ts                  |   32 +
 src/util/loadExcelJs.ts                       |   24 +
 src/util/report.spec.ts                       |   49 +
 src/util/report.ts                            |    7 +
 webpack.config.js                             |    7 +-
 24 files changed, 2707 insertions(+), 259 deletions(-)
 create mode 100644 src/components/ReportForm/FormatDropdown.spec.tsx
 create mode 100644 src/components/ReportForm/FormatDropdown.tsx
 create mode 100644 src/util/InvoicesExcelReport.spec.ts
 create mode 100644 src/util/InvoicesExcelReport.ts
 create mode 100644 src/util/InvoicesReportData.spec.ts
 create mode 100644 src/util/InvoicesReportData.ts
 create mode 100644 src/util/downloadBlob.spec.ts
 create mode 100644 src/util/downloadBlob.ts
 create mode 100644 src/util/loadExcelJs.spec.ts
 create mode 100644 src/util/loadExcelJs.ts
 create mode 100644 src/util/report.spec.ts

diff --git a/package-lock.json b/package-lock.json
index 82cb37f8..552b4ee6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -44,6 +44,7 @@
         "csv-stringify": "^6.7.0",
         "cypress": "^15.14.2",
         "del": "^8.0.1",
+        "exceljs": "^4.4.0",
         "firebase": "^12.13.0",
         "gulp": "^5.0.1",
         "gulp-env": "^0.4.0",
@@ -55,6 +56,7 @@
         "immutability-helper": "^3.1.1",
         "jest": "^30.4.2",
         "jest-environment-jsdom": "^30.4.1",
+        "jszip": "^3.10.1",
         "moment": "^2.30.1",
         "moment-timezone": "^0.6.2",
         "pdfmake": "^0.3.8",
@@ -2379,6 +2381,51 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@fast-csv/format": {
+      "version": "4.3.5",
+      "resolved": "https://registry.npmjs.org/@fast-csv/format/-/format-4.3.5.tgz",
+      "integrity": "sha512-8iRn6QF3I8Ak78lNAa+Gdl5MJJBM5vRHivFtMRUWINdevNo00K7OXxS2PshawLKTejVwieIlPmK5YlLu6w4u8A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "^14.0.1",
+        "lodash.escaperegexp": "^4.1.2",
+        "lodash.isboolean": "^3.0.3",
+        "lodash.isequal": "^4.5.0",
+        "lodash.isfunction": "^3.0.9",
+        "lodash.isnil": "^4.0.0"
+      }
+    },
+    "node_modules/@fast-csv/format/node_modules/@types/node": {
+      "version": "14.18.63",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-14.18.63.tgz",
+      "integrity": "sha512-fAtCfv4jJg+ExtXhvCkCqUKZ+4ok/JQk01qDKhL5BDDoS3AxKXhV5/MAVUZyQnSEd2GT92fkgZl0pz0Q0AzcIQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@fast-csv/parse": {
+      "version": "4.3.6",
+      "resolved": "https://registry.npmjs.org/@fast-csv/parse/-/parse-4.3.6.tgz",
+      "integrity": "sha512-uRsLYksqpbDmWaSmzvJcuApSEe38+6NQZBUsuAyMZKqHxH0g1wcJgsKUvN3WC8tewaqFjBMMGrkHmC+T7k8LvA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "^14.0.1",
+        "lodash.escaperegexp": "^4.1.2",
+        "lodash.groupby": "^4.6.0",
+        "lodash.isfunction": "^3.0.9",
+        "lodash.isnil": "^4.0.0",
+        "lodash.isundefined": "^3.0.1",
+        "lodash.uniq": "^4.5.0"
+      }
+    },
+    "node_modules/@fast-csv/parse/node_modules/@types/node": {
+      "version": "14.18.63",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-14.18.63.tgz",
+      "integrity": "sha512-fAtCfv4jJg+ExtXhvCkCqUKZ+4ok/JQk01qDKhL5BDDoS3AxKXhV5/MAVUZyQnSEd2GT92fkgZl0pz0Q0AzcIQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@firebase/ai": {
       "version": "2.13.1",
       "resolved": "https://registry.npmjs.org/@firebase/ai/-/ai-2.13.1.tgz",
@@ -5236,9 +5283,6 @@
         "arm"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5253,9 +5297,6 @@
         "arm"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5270,9 +5311,6 @@
         "arm64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5287,9 +5325,6 @@
         "arm64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5304,9 +5339,6 @@
         "loong64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5321,9 +5353,6 @@
         "loong64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5338,9 +5367,6 @@
         "ppc64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5355,9 +5381,6 @@
         "ppc64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5372,9 +5395,6 @@
         "riscv64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5389,9 +5409,6 @@
         "riscv64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5406,9 +5423,6 @@
         "s390x"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5423,9 +5437,6 @@
         "x64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -5440,9 +5451,6 @@
         "x64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6437,9 +6445,6 @@
         "arm64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6454,9 +6459,6 @@
         "arm64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6471,9 +6473,6 @@
         "loong64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6488,9 +6487,6 @@
         "loong64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6505,9 +6501,6 @@
         "ppc64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6522,9 +6515,6 @@
         "riscv64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6539,9 +6529,6 @@
         "riscv64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6556,9 +6543,6 @@
         "s390x"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6573,9 +6557,6 @@
         "x64"
       ],
       "dev": true,
-      "libc": [
-        "glibc"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6590,9 +6571,6 @@
         "x64"
       ],
       "dev": true,
-      "libc": [
-        "musl"
-      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -7096,6 +7074,112 @@
       ],
       "license": "MIT"
     },
+    "node_modules/archiver": {
+      "version": "5.3.2",
+      "resolved": "https://registry.npmjs.org/archiver/-/archiver-5.3.2.tgz",
+      "integrity": "sha512-+25nxyyznAXF7Nef3y0EbBeqmGZgeN/BxHX29Rs39djAfaFalmQ89SE6CWyDCHzGL0yt/ycBtNOmGTW0FyGWNw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "archiver-utils": "^2.1.0",
+        "async": "^3.2.4",
+        "buffer-crc32": "^0.2.1",
+        "readable-stream": "^3.6.0",
+        "readdir-glob": "^1.1.2",
+        "tar-stream": "^2.2.0",
+        "zip-stream": "^4.1.0"
+      },
+      "engines": {
+        "node": ">= 10"
+      }
+    },
+    "node_modules/archiver-utils": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/archiver-utils/-/archiver-utils-2.1.0.tgz",
+      "integrity": "sha512-bEL/yUb/fNNiNTuUz979Z0Yg5L+LzLxGJz8x79lYmR54fmTIb6ob/hNQgkQnIUDWIFjZVQwl9Xs356I6BAMHfw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "glob": "^7.1.4",
+        "graceful-fs": "^4.2.0",
+        "lazystream": "^1.0.0",
+        "lodash.defaults": "^4.2.0",
+        "lodash.difference": "^4.5.0",
+        "lodash.flatten": "^4.4.0",
+        "lodash.isplainobject": "^4.0.6",
+        "lodash.union": "^4.6.0",
+        "normalize-path": "^3.0.0",
+        "readable-stream": "^2.0.0"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/archiver-utils/node_modules/isarray": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
+      "integrity": "sha512-VLghIWNM6ELQzo7zwmcg0NmTVyWKYjvIeM83yjp0wRDTmUnrM678fQbcKBo6n2CJEF0szoG//ytg+TKla89ALQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/archiver-utils/node_modules/readable-stream": {
+      "version": "2.3.8",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.8.tgz",
+      "integrity": "sha512-8p0AUk4XODgIewSi0l8Epjs+EVnWiK7NoDIEGU0HhE7+ZyY8D1IMY7odu5lRrFXGg71L15KG8QrPmum45RTtdA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "core-util-is": "~1.0.0",
+        "inherits": "~2.0.3",
+        "isarray": "~1.0.0",
+        "process-nextick-args": "~2.0.0",
+        "safe-buffer": "~5.1.1",
+        "string_decoder": "~1.1.1",
+        "util-deprecate": "~1.0.1"
+      }
+    },
+    "node_modules/archiver-utils/node_modules/safe-buffer": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+      "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/archiver-utils/node_modules/string_decoder": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.1.1.tgz",
+      "integrity": "sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.1.0"
+      }
+    },
+    "node_modules/archiver/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/archiver/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
+    },
     "node_modules/arg": {
       "version": "5.0.2",
       "resolved": "https://registry.npmjs.org/arg/-/arg-5.0.2.tgz",
@@ -7733,6 +7817,30 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/big-integer": {
+      "version": "1.6.52",
+      "resolved": "https://registry.npmjs.org/big-integer/-/big-integer-1.6.52.tgz",
+      "integrity": "sha512-QxD8cf2eVqJOOz63z6JIN9BzvVs/dlySa5HGSBH5xtR8dPteIRQnBxxKqkNTiT6jbDTF6jAfrd4oMcND9RGbQg==",
+      "dev": true,
+      "license": "Unlicense",
+      "engines": {
+        "node": ">=0.6"
+      }
+    },
+    "node_modules/binary": {
+      "version": "0.3.0",
+      "resolved": "https://registry.npmjs.org/binary/-/binary-0.3.0.tgz",
+      "integrity": "sha512-D4H1y5KYwpJgK8wk1Cue5LLPgmwHKYSChkbspQg5JtVuR5ulGckxfR62H3AE9UDkdMC8yyXlqYihuz3Aqg2XZg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "buffers": "~0.1.1",
+        "chainsaw": "~0.1.0"
+      },
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/binary-extensions": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-2.3.0.tgz",
@@ -8015,6 +8123,16 @@
         "ieee754": "^1.1.13"
       }
     },
+    "node_modules/buffer-crc32": {
+      "version": "0.2.13",
+      "resolved": "https://registry.npmjs.org/buffer-crc32/-/buffer-crc32-0.2.13.tgz",
+      "integrity": "sha512-VO9Ht/+p3SN7SKWqcrgEzjGbRSJYTx+Q1pTQC0wrWqHx0vpJraQ6GtHx8tvcg1rlK1byhU5gccxgOgj7B0TDkQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/buffer-from": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
@@ -8022,6 +8140,25 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/buffer-indexof-polyfill": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/buffer-indexof-polyfill/-/buffer-indexof-polyfill-1.0.2.tgz",
+      "integrity": "sha512-I7wzHwA3t1/lwXQh+A5PbNvJxgfo5r3xulgpYDB5zckTu/Z9oUK9biouBKQUjEqzaz3HnAT6TYoovmE+GqSf7A==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.10"
+      }
+    },
+    "node_modules/buffers": {
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/buffers/-/buffers-0.1.1.tgz",
+      "integrity": "sha512-9q/rDEGSb/Qsvv2qvzIzdluL5k7AaJOTrw23z9reQthrbF7is4CtlT0DXyO1oei2DCp4uojjzQ7igaSHp1kAEQ==",
+      "dev": true,
+      "engines": {
+        "node": ">=0.2.0"
+      }
+    },
     "node_modules/bundle-name": {
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/bundle-name/-/bundle-name-4.1.0.tgz",
@@ -8194,6 +8331,19 @@
       "dev": true,
       "license": "Apache-2.0"
     },
+    "node_modules/chainsaw": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/chainsaw/-/chainsaw-0.1.0.tgz",
+      "integrity": "sha512-75kWfWt6MEKNC8xYXIdRpDehRYY/tNSgwKaJq+dbbDcxORuVrrQ+SEHoWsniVn9XPYfP4gmdWIeDk/4YNp1rNQ==",
+      "dev": true,
+      "license": "MIT/X11",
+      "dependencies": {
+        "traverse": ">=0.3.0 <0.4"
+      },
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/chalk": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.2.tgz",
@@ -8620,6 +8770,47 @@
         "node": ">=4.0.0"
       }
     },
+    "node_modules/compress-commons": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/compress-commons/-/compress-commons-4.1.2.tgz",
+      "integrity": "sha512-D3uMHtGc/fcO1Gt1/L7i1e33VOvD4A9hfQLP+6ewd+BvG/gQ84Yh4oftEhAdjSMgBgwGL+jsppT7JYNpo6MHHg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "buffer-crc32": "^0.2.13",
+        "crc32-stream": "^4.0.2",
+        "normalize-path": "^3.0.0",
+        "readable-stream": "^3.6.0"
+      },
+      "engines": {
+        "node": ">= 10"
+      }
+    },
+    "node_modules/compress-commons/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/compress-commons/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
+    },
     "node_modules/compressible": {
       "version": "2.0.18",
       "resolved": "https://registry.npmjs.org/compressible/-/compressible-2.0.18.tgz",
@@ -8781,6 +8972,58 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/crc-32": {
+      "version": "1.2.2",
+      "resolved": "https://registry.npmjs.org/crc-32/-/crc-32-1.2.2.tgz",
+      "integrity": "sha512-ROmzCKrTnOwybPcJApAA6WBWij23HVfGVNKqqrZpuyZOHqK2CwHSvpGuyt/UNNvaIjEd8X5IFGp4Mh+Ie1IHJQ==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "crc32": "bin/crc32.njs"
+      },
+      "engines": {
+        "node": ">=0.8"
+      }
+    },
+    "node_modules/crc32-stream": {
+      "version": "4.0.3",
+      "resolved": "https://registry.npmjs.org/crc32-stream/-/crc32-stream-4.0.3.tgz",
+      "integrity": "sha512-NT7w2JVU7DFroFdYkeq8cywxrgjPHWkdX1wjpRQXPX5Asews3tA+Ght6lddQO5Mkumffp3X7GEqku3epj2toIw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "crc-32": "^1.2.0",
+        "readable-stream": "^3.4.0"
+      },
+      "engines": {
+        "node": ">= 10"
+      }
+    },
+    "node_modules/crc32-stream/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/crc32-stream/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.6",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
@@ -10026,33 +10269,92 @@
         "bare-events": "^2.7.0"
       }
     },
-    "node_modules/execa": {
-      "version": "4.1.0",
-      "resolved": "https://registry.npmjs.org/execa/-/execa-4.1.0.tgz",
-      "integrity": "sha512-j5W0//W7f8UxAn8hXVnwG8tLwdiUy4FJLcSupCg6maBYZDpyBvTApK7KyuI4bKj8KOh1r2YH+6ucuYtJv1bTZA==",
+    "node_modules/exceljs": {
+      "version": "4.4.0",
+      "resolved": "https://registry.npmjs.org/exceljs/-/exceljs-4.4.0.tgz",
+      "integrity": "sha512-XctvKaEMaj1Ii9oDOqbW/6e1gXknSY4g/aLCDicOXqBE4M0nRWkUu0PTp++UPNzoFY12BNHMfs/VadKIS6llvg==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
-        "cross-spawn": "^7.0.0",
-        "get-stream": "^5.0.0",
-        "human-signals": "^1.1.1",
-        "is-stream": "^2.0.0",
-        "merge-stream": "^2.0.0",
-        "npm-run-path": "^4.0.0",
-        "onetime": "^5.1.0",
-        "signal-exit": "^3.0.2",
-        "strip-final-newline": "^2.0.0"
+        "archiver": "^5.0.0",
+        "dayjs": "^1.8.34",
+        "fast-csv": "^4.3.1",
+        "jszip": "^3.10.1",
+        "readable-stream": "^3.6.0",
+        "saxes": "^5.0.1",
+        "tmp": "^0.2.0",
+        "unzipper": "^0.10.11",
+        "uuid": "^8.3.0"
       },
       "engines": {
-        "node": ">=10"
-      },
-      "funding": {
-        "url": "https://github.com/sindresorhus/execa?sponsor=1"
+        "node": ">=8.3.0"
       }
     },
-    "node_modules/executable": {
-      "version": "4.1.1",
-      "resolved": "https://registry.npmjs.org/executable/-/executable-4.1.1.tgz",
+    "node_modules/exceljs/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/exceljs/node_modules/saxes": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/saxes/-/saxes-5.0.1.tgz",
+      "integrity": "sha512-5LBh1Tls8c9xgGjw3QrMwETmTMVk0oFgvrFSvWx62llR2hcEInrKNZ2GZCCuuy2lvWrdl5jhbpeqc5hRYKFOcw==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "xmlchars": "^2.2.0"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
+    "node_modules/exceljs/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
+    },
+    "node_modules/execa": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/execa/-/execa-4.1.0.tgz",
+      "integrity": "sha512-j5W0//W7f8UxAn8hXVnwG8tLwdiUy4FJLcSupCg6maBYZDpyBvTApK7KyuI4bKj8KOh1r2YH+6ucuYtJv1bTZA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "cross-spawn": "^7.0.0",
+        "get-stream": "^5.0.0",
+        "human-signals": "^1.1.1",
+        "is-stream": "^2.0.0",
+        "merge-stream": "^2.0.0",
+        "npm-run-path": "^4.0.0",
+        "onetime": "^5.1.0",
+        "signal-exit": "^3.0.2",
+        "strip-final-newline": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=10"
+      },
+      "funding": {
+        "url": "https://github.com/sindresorhus/execa?sponsor=1"
+      }
+    },
+    "node_modules/executable": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/executable/-/executable-4.1.1.tgz",
       "integrity": "sha512-8iA79xD3uAch729dUG8xaaBBFGaEa0wdD2VkYLFHwlqosEj/jT66AzcreRDSgV7ehnNLBW2WR5jIXwGKjVdTLg==",
       "dev": true,
       "license": "MIT",
@@ -10225,6 +10527,20 @@
         "node": ">= 0.10"
       }
     },
+    "node_modules/fast-csv": {
+      "version": "4.3.6",
+      "resolved": "https://registry.npmjs.org/fast-csv/-/fast-csv-4.3.6.tgz",
+      "integrity": "sha512-2RNSpuwwsJGP0frGsOmTb9oUF+VkFSM4SyLTDgwf2ciHWTarN0lQTC+F2f/t5J9QjW+c65VFIAAu85GsvMIusw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@fast-csv/format": "4.3.5",
+        "@fast-csv/parse": "4.3.6"
+      },
+      "engines": {
+        "node": ">=10.0.0"
+      }
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -10693,6 +11009,13 @@
         "node": ">= 0.6"
       }
     },
+    "node_modules/fs-constants": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/fs-constants/-/fs-constants-1.0.0.tgz",
+      "integrity": "sha512-y6OAwoSIf7FyjMIv94u+b5rdheZEjzR63GTyZJm5qh4Bi+2YgwLCcI/fPFZkL5PSixOt6ZNKm+w+Hfp/Bciwow==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/fs-extra": {
       "version": "9.1.0",
       "resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-9.1.0.tgz",
@@ -10752,6 +11075,23 @@
         "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
       }
     },
+    "node_modules/fstream": {
+      "version": "1.0.12",
+      "resolved": "https://registry.npmjs.org/fstream/-/fstream-1.0.12.tgz",
+      "integrity": "sha512-WvJ193OHa0GHPEL+AycEJgxvBEwyfRkN1vhjca23OaPVMCaLCXTd5qAu82AjTcgP1UJmytkOKb63Ypde7raDIg==",
+      "deprecated": "This package is no longer supported.",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "graceful-fs": "^4.1.2",
+        "inherits": "~2.0.0",
+        "mkdirp": ">=0.5 0",
+        "rimraf": "2"
+      },
+      "engines": {
+        "node": ">=0.6"
+      }
+    },
     "node_modules/function-bind": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.2.tgz",
@@ -12203,6 +12543,13 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/immediate": {
+      "version": "3.0.6",
+      "resolved": "https://registry.npmjs.org/immediate/-/immediate-3.0.6.tgz",
+      "integrity": "sha512-XXOFtyqDjNDAQxVfYxuF7g9Il/IbWmmlQg2MYKOH8ExIT1qg6xc4zyS3HaEEATgs1btfzxq15ciUiY7gjSXRGQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/immutability-helper": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/immutability-helper/-/immutability-helper-3.1.1.tgz",
@@ -14559,6 +14906,59 @@
         "verror": "1.10.0"
       }
     },
+    "node_modules/jszip": {
+      "version": "3.10.1",
+      "resolved": "https://registry.npmjs.org/jszip/-/jszip-3.10.1.tgz",
+      "integrity": "sha512-xXDvecyTpGLrqFrvkrUSoxxfJI5AH7U8zxxtVclpsUtMCq4JQ290LY8AW5c7Ggnr/Y/oK+bQMbqK2qmtk3pN4g==",
+      "dev": true,
+      "license": "(MIT OR GPL-3.0-or-later)",
+      "dependencies": {
+        "lie": "~3.3.0",
+        "pako": "~1.0.2",
+        "readable-stream": "~2.3.6",
+        "setimmediate": "^1.0.5"
+      }
+    },
+    "node_modules/jszip/node_modules/isarray": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
+      "integrity": "sha512-VLghIWNM6ELQzo7zwmcg0NmTVyWKYjvIeM83yjp0wRDTmUnrM678fQbcKBo6n2CJEF0szoG//ytg+TKla89ALQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/jszip/node_modules/readable-stream": {
+      "version": "2.3.8",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.8.tgz",
+      "integrity": "sha512-8p0AUk4XODgIewSi0l8Epjs+EVnWiK7NoDIEGU0HhE7+ZyY8D1IMY7odu5lRrFXGg71L15KG8QrPmum45RTtdA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "core-util-is": "~1.0.0",
+        "inherits": "~2.0.3",
+        "isarray": "~1.0.0",
+        "process-nextick-args": "~2.0.0",
+        "safe-buffer": "~5.1.1",
+        "string_decoder": "~1.1.1",
+        "util-deprecate": "~1.0.1"
+      }
+    },
+    "node_modules/jszip/node_modules/safe-buffer": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+      "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/jszip/node_modules/string_decoder": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.1.1.tgz",
+      "integrity": "sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.1.0"
+      }
+    },
     "node_modules/kind-of": {
       "version": "6.0.3",
       "resolved": "https://registry.npmjs.org/kind-of/-/kind-of-6.0.3.tgz",
@@ -14600,6 +15000,59 @@
         "node": "> 0.8"
       }
     },
+    "node_modules/lazystream": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/lazystream/-/lazystream-1.0.1.tgz",
+      "integrity": "sha512-b94GiNHQNy6JNTrt5w6zNyffMrNkXZb3KTkCZJb2V1xaEGCk093vkZ2jk3tpaeP33/OiXC+WvK9AxUebnf5nbw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "readable-stream": "^2.0.5"
+      },
+      "engines": {
+        "node": ">= 0.6.3"
+      }
+    },
+    "node_modules/lazystream/node_modules/isarray": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
+      "integrity": "sha512-VLghIWNM6ELQzo7zwmcg0NmTVyWKYjvIeM83yjp0wRDTmUnrM678fQbcKBo6n2CJEF0szoG//ytg+TKla89ALQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lazystream/node_modules/readable-stream": {
+      "version": "2.3.8",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.8.tgz",
+      "integrity": "sha512-8p0AUk4XODgIewSi0l8Epjs+EVnWiK7NoDIEGU0HhE7+ZyY8D1IMY7odu5lRrFXGg71L15KG8QrPmum45RTtdA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "core-util-is": "~1.0.0",
+        "inherits": "~2.0.3",
+        "isarray": "~1.0.0",
+        "process-nextick-args": "~2.0.0",
+        "safe-buffer": "~5.1.1",
+        "string_decoder": "~1.1.1",
+        "util-deprecate": "~1.0.1"
+      }
+    },
+    "node_modules/lazystream/node_modules/safe-buffer": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+      "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lazystream/node_modules/string_decoder": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.1.1.tgz",
+      "integrity": "sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.1.0"
+      }
+    },
     "node_modules/lead": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/lead/-/lead-4.0.0.tgz",
@@ -14620,6 +15073,16 @@
         "node": ">=6"
       }
     },
+    "node_modules/lie": {
+      "version": "3.3.0",
+      "resolved": "https://registry.npmjs.org/lie/-/lie-3.3.0.tgz",
+      "integrity": "sha512-UaiMJzeWRlEujzAuw5LokY1L5ecNQYZKfmyZ9L7wDHb/p5etKaxXhohBcrw0EYby+G/NA52vRSN4N39dxHAIwQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "immediate": "~3.0.5"
+      }
+    },
     "node_modules/liftoff": {
       "version": "5.0.1",
       "resolved": "https://registry.npmjs.org/liftoff/-/liftoff-5.0.1.tgz",
@@ -14667,6 +15130,13 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/listenercount": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/listenercount/-/listenercount-1.0.1.tgz",
+      "integrity": "sha512-3mk/Zag0+IJxeDrxSgaDPy4zZ3w05PRZeJNnlWhzFz5OkX49J4krc+A8X2d2M69vGMBEX0uyl8M+W+8gH+kBqQ==",
+      "dev": true,
+      "license": "ISC"
+    },
     "node_modules/listr2": {
       "version": "9.0.5",
       "resolved": "https://registry.npmjs.org/listr2/-/listr2-9.0.5.tgz",
@@ -14807,6 +15277,20 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/lodash.defaults": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/lodash.defaults/-/lodash.defaults-4.2.0.tgz",
+      "integrity": "sha512-qjxPLHd3r5DnsdGacqOMU6pb/avJzdh9tFX2ymgoZE27BmjXrNy/y4LoaiTeAb+O3gL8AfpJGtqfX/ae2leYYQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.difference": {
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/lodash.difference/-/lodash.difference-4.5.0.tgz",
+      "integrity": "sha512-dS2j+W26TQ7taQBGN8Lbbq04ssV3emRw4NY58WErlTO29pIqS0HmoT5aJ9+TUQ1N3G+JOZSji4eugsWwGp9yPA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/lodash.escape": {
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/lodash.escape/-/lodash.escape-3.2.0.tgz",
@@ -14817,6 +15301,27 @@
         "lodash._root": "^3.0.0"
       }
     },
+    "node_modules/lodash.escaperegexp": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/lodash.escaperegexp/-/lodash.escaperegexp-4.1.2.tgz",
+      "integrity": "sha512-TM9YBvyC84ZxE3rgfefxUWiQKLilstD6k7PTGt6wfbtXF8ixIJLOL3VYyV/z+ZiPLsVxAsKAFVwWlWeb2Y8Yyw==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.flatten": {
+      "version": "4.4.0",
+      "resolved": "https://registry.npmjs.org/lodash.flatten/-/lodash.flatten-4.4.0.tgz",
+      "integrity": "sha512-C5N2Z3DgnnKr0LOpv/hKCgKdb7ZZwafIrsesve6lmzvZIRZRGaZ/l6Q8+2W7NaT+ZwO3fFlSCzCzrDCFdJfZ4g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.groupby": {
+      "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/lodash.groupby/-/lodash.groupby-4.6.0.tgz",
+      "integrity": "sha512-5dcWxm23+VAoz+awKmBaiBvzox8+RqMgFhi7UvX9DHZr2HdxHXM/Wrf8cfKpsW37RNrvtPn6hSwNqurSILbmJw==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/lodash.isarguments": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/lodash.isarguments/-/lodash.isarguments-3.1.0.tgz",
@@ -14831,6 +15336,49 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/lodash.isboolean": {
+      "version": "3.0.3",
+      "resolved": "https://registry.npmjs.org/lodash.isboolean/-/lodash.isboolean-3.0.3.tgz",
+      "integrity": "sha512-Bz5mupy2SVbPHURB98VAcw+aHh4vRV5IPNhILUCsOzRmsTmSQ17jIuqopAentWoehktxGd9e/hbIXq980/1QJg==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.isequal": {
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/lodash.isequal/-/lodash.isequal-4.5.0.tgz",
+      "integrity": "sha512-pDo3lu8Jhfjqls6GkMgpahsF9kCyayhgykjyLMNFTKWrpVdAQtYyB4muAMWozBB4ig/dtWAmsMxLEI8wuz+DYQ==",
+      "deprecated": "This package is deprecated. Use require('node:util').isDeepStrictEqual instead.",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.isfunction": {
+      "version": "3.0.9",
+      "resolved": "https://registry.npmjs.org/lodash.isfunction/-/lodash.isfunction-3.0.9.tgz",
+      "integrity": "sha512-AirXNj15uRIMMPihnkInB4i3NHeb4iBtNg9WRWuK2o31S+ePwwNmDPaTL3o7dTJ+VXNZim7rFs4rxN4YU1oUJw==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.isnil": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/lodash.isnil/-/lodash.isnil-4.0.0.tgz",
+      "integrity": "sha512-up2Mzq3545mwVnMhTDMdfoG1OurpA/s5t88JmQX809eH3C8491iu2sfKhTfhQtKY78oPNhiaHJUpT/dUDAAtng==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.isplainobject": {
+      "version": "4.0.6",
+      "resolved": "https://registry.npmjs.org/lodash.isplainobject/-/lodash.isplainobject-4.0.6.tgz",
+      "integrity": "sha512-oSXzaWypCMHkPC3NvBEaPHf0KsA5mvPrOPgQWDsbg8n7orZ290M0BmC/jgRZ4vcJ6DTAhjrsSYgdsW/F+MFOBA==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.isundefined": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/lodash.isundefined/-/lodash.isundefined-3.0.1.tgz",
+      "integrity": "sha512-MXB1is3s899/cD8jheYYE2V9qTHwKvt+npCwpD+1Sxm3Q3cECXCiYHjeHWXNwr6Q0SOBPrYUDxendrO6goVTEA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/lodash.keys": {
       "version": "3.1.2",
       "resolved": "https://registry.npmjs.org/lodash.keys/-/lodash.keys-3.1.2.tgz",
@@ -14901,6 +15449,20 @@
         "lodash.escape": "^3.0.0"
       }
     },
+    "node_modules/lodash.union": {
+      "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/lodash.union/-/lodash.union-4.6.0.tgz",
+      "integrity": "sha512-c4pB2CdGrGdjMKYLA+XiRDO7Y0PRQbm/Gzg8qMj+QH+pFVAoTp5sBpO0odL3FjoPCGjK96p6qsP+yQoiLoOBcw==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.uniq": {
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/lodash.uniq/-/lodash.uniq-4.5.0.tgz",
+      "integrity": "sha512-xfBaXQd9ryd9dlSDvnvI0lvxfLJlYAZzXomUYzLKtUeOQvOP5piqAWuGtrhWeqaXK9hhoM/iyJc5AV+XfsX3HQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/log-symbols": {
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/log-symbols/-/log-symbols-4.1.0.tgz",
@@ -15376,6 +15938,19 @@
         "node": ">=16 || 14 >=14.17"
       }
     },
+    "node_modules/mkdirp": {
+      "version": "0.5.6",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.6.tgz",
+      "integrity": "sha512-FP+p8RB8OWpF3YZBCrP5gtADmtXApB5AMLn+vdyA+PyxCjrCs00mjyUozssO33cwDeT3wNGdLxJ5M//YqtHAJw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "minimist": "^1.2.6"
+      },
+      "bin": {
+        "mkdirp": "bin/cmd.js"
+      }
+    },
     "node_modules/moment": {
       "version": "2.30.1",
       "resolved": "https://registry.npmjs.org/moment/-/moment-2.30.1.tgz",
@@ -16997,6 +17572,39 @@
         "string_decoder": "~0.10.x"
       }
     },
+    "node_modules/readdir-glob": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/readdir-glob/-/readdir-glob-1.1.3.tgz",
+      "integrity": "sha512-v05I2k7xN8zXvPD9N+z/uhXPaj0sUFCe2rcWZIpBsqxfP7xXFQ0tipAd/wjj1YxWyWtUS5IDJpOG82JKt2EAVA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "minimatch": "^5.1.0"
+      }
+    },
+    "node_modules/readdir-glob/node_modules/brace-expansion": {
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-2.1.4.tgz",
+      "integrity": "sha512-hGfVzPxthbf3+2yjg/RBs60cB0FhqBS/zvdV/4wn4/BmN0bNMMHPc4V/BbFieqf1TKAGGAHnY4eSjajCl0f2Xg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "balanced-match": "^1.0.0"
+      }
+    },
+    "node_modules/readdir-glob/node_modules/minimatch": {
+      "version": "5.1.9",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-5.1.9.tgz",
+      "integrity": "sha512-7o1wEA2RyMP7Iu7GNba9vc0RWWGACJOCZBJX2GJWip0ikV+wcOsgVuY9uE8CPiyQhkGFSlhuSkZPavN7u1c2Fw==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "brace-expansion": "^2.0.1"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/readdirp": {
       "version": "3.6.0",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-3.6.0.tgz",
@@ -17424,6 +18032,20 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/rimraf": {
+      "version": "2.7.1",
+      "resolved": "https://registry.npmjs.org/rimraf/-/rimraf-2.7.1.tgz",
+      "integrity": "sha512-uWjbaKIK3T1OSVptzX7Nl6PvQ3qAGtKEtVRjRuazjfL3Bx5eI409VZSqgND+4UNnmzLVdPj9FqFJNPqBZFve4w==",
+      "deprecated": "Rimraf versions prior to v4 are no longer supported",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "glob": "^7.1.3"
+      },
+      "bin": {
+        "rimraf": "bin.js"
+      }
+    },
     "node_modules/rollup": {
       "version": "4.62.2",
       "resolved": "https://registry.npmjs.org/rollup/-/rollup-4.62.2.tgz",
@@ -17929,6 +18551,13 @@
         "node": ">= 0.4"
       }
     },
+    "node_modules/setimmediate": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/setimmediate/-/setimmediate-1.0.5.tgz",
+      "integrity": "sha512-MATJdZp8sLqDl/68LfQmbP8zKPLQNV6BIZoIgrscFDQ+RsvK/BxeDQOgyxKKoh0y/8h3BqVFnCqQ/gd+reiIXA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/setprototypeof": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/setprototypeof/-/setprototypeof-1.2.0.tgz",
@@ -18915,6 +19544,60 @@
         "url": "https://opencollective.com/webpack"
       }
     },
+    "node_modules/tar-stream": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/tar-stream/-/tar-stream-2.2.0.tgz",
+      "integrity": "sha512-ujeqbceABgwMZxEJnk2HDY2DlnUZ+9oEcb1KzTVfYHio0UE6dG71n60d8D2I4qNvleWrrXpmjpt7vZeF1LnMZQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "bl": "^4.0.3",
+        "end-of-stream": "^1.4.1",
+        "fs-constants": "^1.0.0",
+        "inherits": "^2.0.3",
+        "readable-stream": "^3.1.1"
+      },
+      "engines": {
+        "node": ">=6"
+      }
+    },
+    "node_modules/tar-stream/node_modules/bl": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/bl/-/bl-4.1.0.tgz",
+      "integrity": "sha512-1W07cM9gS6DcLperZfFSj+bWLtaPGSOHWhPiGzXmvVJbRLdG82sH/Kn8EtW1VqWVA54AKf2h5k5BbnIbwF3h6w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "buffer": "^5.5.0",
+        "inherits": "^2.0.4",
+        "readable-stream": "^3.4.0"
+      }
+    },
+    "node_modules/tar-stream/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/tar-stream/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
+    },
     "node_modules/teex": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/teex/-/teex-1.0.1.tgz",
@@ -19329,6 +20012,16 @@
         "node": ">=18"
       }
     },
+    "node_modules/traverse": {
+      "version": "0.3.9",
+      "resolved": "https://registry.npmjs.org/traverse/-/traverse-0.3.9.tgz",
+      "integrity": "sha512-iawgk0hLP3SxGKDfnDJf8wTz4p2qImnyihM5Hh/sGvQ3K37dPi/w8sRhdNIxYA1TwFwc5mDhIJq+O0RsvXBKdQ==",
+      "dev": true,
+      "license": "MIT/X11",
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/tree-dump": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/tree-dump/-/tree-dump-1.1.0.tgz",
@@ -19751,6 +20444,82 @@
         "node": ">=8"
       }
     },
+    "node_modules/unzipper": {
+      "version": "0.10.14",
+      "resolved": "https://registry.npmjs.org/unzipper/-/unzipper-0.10.14.tgz",
+      "integrity": "sha512-ti4wZj+0bQTiX2KmKWuwj7lhV+2n//uXEotUmGuQqrbVZSEGFMbI68+c6JCQ8aAmUWYvtHEz2A8K6wXvueR/6g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "big-integer": "^1.6.17",
+        "binary": "~0.3.0",
+        "bluebird": "~3.4.1",
+        "buffer-indexof-polyfill": "~1.0.0",
+        "duplexer2": "~0.1.4",
+        "fstream": "^1.0.12",
+        "graceful-fs": "^4.2.2",
+        "listenercount": "~1.0.1",
+        "readable-stream": "~2.3.6",
+        "setimmediate": "~1.0.4"
+      }
+    },
+    "node_modules/unzipper/node_modules/bluebird": {
+      "version": "3.4.7",
+      "resolved": "https://registry.npmjs.org/bluebird/-/bluebird-3.4.7.tgz",
+      "integrity": "sha512-iD3898SR7sWVRHbiQv+sHUtHnMvC1o3nW5rAcqnq3uOn07DSAppZYUkIGslDz6gXC7HfunPe7YVBgoEJASPcHA==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/unzipper/node_modules/duplexer2": {
+      "version": "0.1.4",
+      "resolved": "https://registry.npmjs.org/duplexer2/-/duplexer2-0.1.4.tgz",
+      "integrity": "sha512-asLFVfWWtJ90ZyOUHMqk7/S2w2guQKxUI2itj3d92ADHhxUSbCMGi1f1cBcJ7xM1To+pE/Khbwo1yuNbMEPKeA==",
+      "dev": true,
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "readable-stream": "^2.0.2"
+      }
+    },
+    "node_modules/unzipper/node_modules/isarray": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
+      "integrity": "sha512-VLghIWNM6ELQzo7zwmcg0NmTVyWKYjvIeM83yjp0wRDTmUnrM678fQbcKBo6n2CJEF0szoG//ytg+TKla89ALQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/unzipper/node_modules/readable-stream": {
+      "version": "2.3.8",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.8.tgz",
+      "integrity": "sha512-8p0AUk4XODgIewSi0l8Epjs+EVnWiK7NoDIEGU0HhE7+ZyY8D1IMY7odu5lRrFXGg71L15KG8QrPmum45RTtdA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "core-util-is": "~1.0.0",
+        "inherits": "~2.0.3",
+        "isarray": "~1.0.0",
+        "process-nextick-args": "~2.0.0",
+        "safe-buffer": "~5.1.1",
+        "string_decoder": "~1.1.1",
+        "util-deprecate": "~1.0.1"
+      }
+    },
+    "node_modules/unzipper/node_modules/safe-buffer": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+      "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/unzipper/node_modules/string_decoder": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.1.1.tgz",
+      "integrity": "sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.1.0"
+      }
+    },
     "node_modules/upath": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/upath/-/upath-1.2.0.tgz",
@@ -21343,6 +22112,68 @@
       "funding": {
         "url": "https://github.com/sponsors/sindresorhus"
       }
+    },
+    "node_modules/zip-stream": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/zip-stream/-/zip-stream-4.1.1.tgz",
+      "integrity": "sha512-9qv4rlDiopXg4E69k+vMHjNN63YFMe9sZMrdlvKnCjlCRWeCBswPPMPUfx+ipsAWq1LXHe70RcbaHdJJpS6hyQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "archiver-utils": "^3.0.4",
+        "compress-commons": "^4.1.2",
+        "readable-stream": "^3.6.0"
+      },
+      "engines": {
+        "node": ">= 10"
+      }
+    },
+    "node_modules/zip-stream/node_modules/archiver-utils": {
+      "version": "3.0.4",
+      "resolved": "https://registry.npmjs.org/archiver-utils/-/archiver-utils-3.0.4.tgz",
+      "integrity": "sha512-KVgf4XQVrTjhyWmx6cte4RxonPLR9onExufI1jhvw/MQ4BB6IsZD5gT8Lq+u/+pRkWna/6JoHpiQioaqFP5Rzw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "glob": "^7.2.3",
+        "graceful-fs": "^4.2.0",
+        "lazystream": "^1.0.0",
+        "lodash.defaults": "^4.2.0",
+        "lodash.difference": "^4.5.0",
+        "lodash.flatten": "^4.4.0",
+        "lodash.isplainobject": "^4.0.6",
+        "lodash.union": "^4.6.0",
+        "normalize-path": "^3.0.0",
+        "readable-stream": "^3.6.0"
+      },
+      "engines": {
+        "node": ">= 10"
+      }
+    },
+    "node_modules/zip-stream/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/zip-stream/node_modules/string_decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
+      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "safe-buffer": "~5.2.0"
+      }
     }
   }
 }
diff --git a/package.json b/package.json
index b4374449..083397e8 100644
--- a/package.json
+++ b/package.json
@@ -47,6 +47,7 @@
     "csv-stringify": "^6.7.0",
     "cypress": "^15.14.2",
     "del": "^8.0.1",
+    "exceljs": "^4.4.0",
     "firebase": "^12.13.0",
     "gulp": "^5.0.1",
     "gulp-env": "^0.4.0",
@@ -58,6 +59,7 @@
     "immutability-helper": "^3.1.1",
     "jest": "^30.4.2",
     "jest-environment-jsdom": "^30.4.1",
+    "jszip": "^3.10.1",
     "moment": "^2.30.1",
     "moment-timezone": "^0.6.2",
     "pdfmake": "^0.3.8",
diff --git a/src/components/ReportForm/FormatDropdown.spec.tsx b/src/components/ReportForm/FormatDropdown.spec.tsx
new file mode 100644
index 00000000..524abebf
--- /dev/null
+++ b/src/components/ReportForm/FormatDropdown.spec.tsx
@@ -0,0 +1,45 @@
+import React from 'react';
+import { renderWithTheme, screen, fireEvent } from '../../../test/renderWithTheme';
+import FormatDropdown from './FormatDropdown';
+
+jest.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: key => key }),
+  withTranslation: () => Component => Component,
+}));
+
+jest.mock('scroll-into-view', () => jest.fn());
+
+describe('FormatDropdown', () => {
+  it('renders an input element', () => {
+    renderWithTheme(<FormatDropdown onChange={jest.fn()} />);
+    expect(screen.getByRole('textbox')).toBeInTheDocument();
+  });
+
+  it('offers the pdf and excel options when focused', () => {
+    renderWithTheme(<FormatDropdown onChange={jest.fn()} />);
+    fireEvent.focus(screen.getByRole('textbox'));
+    expect(screen.getByText('invoicesReport.formatPdf')).toBeInTheDocument();
+    expect(screen.getByText('invoicesReport.formatExcel')).toBeInTheDocument();
+  });
+
+  it('calls onChange with the selected format key', () => {
+    const onChange = jest.fn();
+    renderWithTheme(<FormatDropdown onChange={onChange} />);
+    fireEvent.focus(screen.getByRole('textbox'));
+    fireEvent.mouseDown(screen.getByText('invoicesReport.formatExcel'));
+    expect(onChange).toHaveBeenCalledWith('excel');
+  });
+
+  it('renders the current value', () => {
+    renderWithTheme(<FormatDropdown value="excel" onChange={jest.fn()} />);
+    expect(screen.getByRole('textbox')).toHaveValue('invoicesReport.formatExcel');
+  });
+
+  it('does not throw when no onChange is given', () => {
+    renderWithTheme(<FormatDropdown />);
+    fireEvent.focus(screen.getByRole('textbox'));
+    expect(() =>
+      fireEvent.mouseDown(screen.getByText('invoicesReport.formatPdf'))
+    ).not.toThrow();
+  });
+});
diff --git a/src/components/ReportForm/FormatDropdown.tsx b/src/components/ReportForm/FormatDropdown.tsx
new file mode 100644
index 00000000..562bd0aa
--- /dev/null
+++ b/src/components/ReportForm/FormatDropdown.tsx
@@ -0,0 +1,57 @@
+import PropTypes from 'prop-types';
+import React from 'react';
+import styled from 'styled-components';
+import Dropdown from '../Dropdown';
+import { useTranslation } from 'react-i18next';
+
+const Option = styled.div`
+  padding: 0.2em;
+`;
+
+const filterOptions = (options, filter) =>
+  options.filter(option => option.label.toUpperCase().indexOf(filter.toUpperCase()) > -1);
+
+const renderOption = option => <Option>{option.label}</Option>;
+
+const renderValue = option => option.label;
+
+const handleChange = (onChange, value) => {
+  if (typeof onChange === 'function') {
+    onChange(value);
+  }
+};
+
+const FormatDropdown = props => {
+  const { t } = useTranslation();
+  const options = [{
+    key: 'pdf',
+    label: t('invoicesReport.formatPdf')
+  }, {
+    key: 'excel',
+    label: t('invoicesReport.formatExcel')
+  }];
+  return (
+    <Dropdown
+      className={props.className}
+      options={options}
+      value={props.value}
+      onChange={handleChange.bind(null, props.onChange)}
+      readOnly={props.readOnly}
+      optionFilter={filterOptions}
+      optionRenderer={renderOption}
+      valueRenderer={renderValue}
+      optionsRenderLimit={options.length}
+      noOptionsText={t('dropdown.notFound')}
+      mustSelect
+    />
+  );
+};
+
+FormatDropdown.propTypes = {
+  className: PropTypes.string,
+  value: PropTypes.string,
+  onChange: PropTypes.func,
+  readOnly: PropTypes.bool
+};
+
+export default FormatDropdown;
diff --git a/src/components/ReportForm/ReportForm.spec.tsx b/src/components/ReportForm/ReportForm.spec.tsx
index a012708e..0d42e699 100644
--- a/src/components/ReportForm/ReportForm.spec.tsx
+++ b/src/components/ReportForm/ReportForm.spec.tsx
@@ -82,6 +82,22 @@ jest.mock('./DelimiterDropdown', () => {
   };
 });
 
+jest.mock('./FormatDropdown', () => {
+  const React = require('react');
+  return function MockFormatDropdown({ value, onChange }) {
+    return (
+      <select
+        data-testid="format-dropdown"
+        value={value}
+        onChange={e => onChange(e.target.value)}
+      >
+        <option value="pdf">pdf</option>
+        <option value="excel">excel</option>
+      </select>
+    );
+  };
+});
+
 import ReportForm from './ReportForm';
 
 const baseProps = {
@@ -124,6 +140,30 @@ describe('ReportForm', () => {
     expect(screen.getByTestId('delimiter-dropdown')).toBeInTheDocument();
   });
 
+  it('does not render format dropdown by default', () => {
+    renderWithTheme(<ReportForm {...baseProps} />);
+    expect(screen.queryByTestId('format-dropdown')).not.toBeInTheDocument();
+  });
+
+  it('renders format dropdown when withFormat is true', () => {
+    renderWithTheme(<ReportForm {...baseProps} withFormat={true} setFormat={jest.fn()} />);
+    expect(screen.getByTestId('format-dropdown')).toBeInTheDocument();
+  });
+
+  it('passes the format value through to the dropdown', () => {
+    renderWithTheme(
+      <ReportForm {...baseProps} withFormat={true} format="excel" setFormat={jest.fn()} />
+    );
+    expect(screen.getByTestId('format-dropdown')).toHaveValue('excel');
+  });
+
+  it('calls setFormat when the format dropdown changes', () => {
+    const setFormat = jest.fn();
+    renderWithTheme(<ReportForm {...baseProps} withFormat={true} setFormat={setFormat} />);
+    fireEvent.change(screen.getByTestId('format-dropdown'), { target: { value: 'excel' } });
+    expect(setFormat).toHaveBeenCalledWith('excel');
+  });
+
   it('does not render delimiter dropdown when withDelimiter is false', () => {
     renderWithTheme(<ReportForm {...baseProps} withDelimiter={false} />);
     expect(screen.queryByTestId('delimiter-dropdown')).not.toBeInTheDocument();
diff --git a/src/components/ReportForm/ReportForm.tsx b/src/components/ReportForm/ReportForm.tsx
index 87d18998..71b8ec9b 100644
--- a/src/components/ReportForm/ReportForm.tsx
+++ b/src/components/ReportForm/ReportForm.tsx
@@ -7,6 +7,7 @@ import Button from '../Button';
 import LabeledComponent from '../LabeledComponent';
 import MonthDropdown from '../MonthDropdown';
 import DelimiterDropdown from './DelimiterDropdown';
+import FormatDropdown from './FormatDropdown';
 
 const StyledLabeledComponent = styled(LabeledComponent)`
   width: 50%;
@@ -52,10 +53,13 @@ const ReportForm = ({
   children,
   date,
   delimiter = ',',
+  format = 'pdf',
   withMonth = true,
   withDelimiter = true,
+  withFormat = false,
   setDate,
   setDelimiter,
+  setFormat,
   generate,
   parameters,
 }: {
@@ -63,10 +67,13 @@ const ReportForm = ({
   children?: React.ReactNode;
   date?: { year?: number | null; month?: number | null };
   delimiter?: string;
+  format?: string;
   withMonth?: boolean;
   withDelimiter?: boolean;
+  withFormat?: boolean;
   setDate: (date: any) => void;
   setDelimiter?: (delimiter: string) => void;
+  setFormat?: (format: string) => void;
   generate: (date: any, parameters: any) => void;
   parameters?: any;
 }) => {
@@ -95,6 +102,13 @@ const ReportForm = ({
     />
   )
 
+  const formatInput = (
+    <FormatDropdown
+      value={format}
+      onChange={setFormat}
+    />
+  )
+
   return (
     <form
       className="ReportForm"
@@ -104,6 +118,7 @@ const ReportForm = ({
         <StyledLabeledComponent label={t('report.year')} component={yearInput}/>
         {withMonth && <StyledLabeledComponent label={t('report.month')} component={monthInput}/>}
         {withDelimiter && <StyledLabeledComponent label={t('report.delimiter')} component={delimiterInput}/>}
+        {withFormat && <StyledLabeledComponent label={t('report.format')} component={formatInput}/>}
         {children}
         <Button
           type="submit"
@@ -124,10 +139,13 @@ ReportForm.propTypes = {
     month: PropTypes.number,
   }),
   delimiter: PropTypes.string,
+  format: PropTypes.string,
   withMonth: PropTypes.bool,
   withDelimiter: PropTypes.bool,
+  withFormat: PropTypes.bool,
   setDate: PropTypes.func.isRequired,
   setDelimiter: PropTypes.func,
+  setFormat: PropTypes.func,
   generate: PropTypes.func.isRequired,
 };
 
diff --git a/src/containers/InvoicesReportFormContainer.tsx b/src/containers/InvoicesReportFormContainer.tsx
index f41b9713..5d08f412 100644
--- a/src/containers/InvoicesReportFormContainer.tsx
+++ b/src/containers/InvoicesReportFormContainer.tsx
@@ -1,6 +1,6 @@
 import React, { useEffect } from 'react';
 import {connect} from 'react-redux';
-import {generateReport, initReport, setReportDate} from '../modules/reports';
+import {generateReport, initReport, setReportDate, setReportParameter} from '../modules/reports';
 import ReportForm from '../components/ReportForm';
 import {RootState} from '../modules';
 
@@ -12,9 +12,11 @@ interface ReportDate {
 interface Props {
   initialized: boolean;
   date?: ReportDate;
+  format?: string;
   generationInProgress?: boolean;
   initReport: () => void;
   setDate: (date: ReportDate) => void;
+  setFormat: (format: string) => void;
   generate: () => void;
 }
 
@@ -28,9 +30,12 @@ const InvoicesReportFormContainer = (props: Props) => {
     <ReportForm
       disabled={!props.initialized || props.generationInProgress}
       date={props.date}
+      format={props.format}
       setDate={props.setDate}
+      setFormat={props.setFormat}
       generate={props.generate}
       withDelimiter={false}
+      withFormat
     />
   );
 };
@@ -47,6 +52,7 @@ const mapStateToProps = (state: RootState) => {
   return {
     initialized,
     date: report.date,
+    format: report.parameters.format || 'pdf',
     generationInProgress: report.generationInProgress === true,
   };
 };
@@ -54,6 +60,8 @@ const mapStateToProps = (state: RootState) => {
 const mapDispatchToProps = (dispatch: any) => ({
   initReport: () => dispatch(initReport('invoices')),
   setDate: (date: any) => dispatch(setReportDate('invoices', date)),
+  setFormat: (format: string) =>
+    dispatch(setReportParameter('invoices', 'format', format)),
   generate: () => dispatch(generateReport('invoices')),
 });
 
diff --git a/src/containers/containers.spec.tsx b/src/containers/containers.spec.tsx
index a0365d3a..f9a50a09 100644
--- a/src/containers/containers.spec.tsx
+++ b/src/containers/containers.spec.tsx
@@ -90,10 +90,17 @@ jest.mock('../components/YearlySummaryReportForm', () => ({
   default: () => <div data-testid="yearly-summary-report-form" />,
 }));
 
-jest.mock('../components/ReportForm', () => ({
-  __esModule: true,
-  default: () => <div data-testid="report-form" />,
-}));
+// A jest.fn() wrapper (rather than a plain stub) so the invoices format
+// wiring test below can inspect the props InvoicesReportFormContainer passes
+// down and drive its setFormat callback directly.
+jest.mock('../components/ReportForm', () => {
+  const React = require('react');
+  const mockReportForm = jest.fn((_props: any) => React.createElement('div', {'data-testid': 'report-form'}));
+  return {
+    __esModule: true,
+    default: mockReportForm,
+  };
+});
 
 jest.mock('../components/AirstatReportForm', () => ({
   __esModule: true,
@@ -239,6 +246,42 @@ describe('container mount dispatches', () => {
     expect(inits[0].payload.name).toBe('invoices');
   });
 
+  it('InvoicesReportFormContainer defaults format to pdf when no parameter is set', () => {
+    const store = makeStore({ reports: { invoices: { date: {}, parameters: {} } } });
+    render(wrap(store, <InvoicesReportFormContainer />));
+    const ReportForm = require('../components/ReportForm').default;
+    const lastProps = ReportForm.mock.calls[ReportForm.mock.calls.length - 1][0];
+    expect(lastProps.format).toBe('pdf');
+    expect(lastProps.withFormat).toBe(true);
+  });
+
+  it('InvoicesReportFormContainer passes through a format already in state', () => {
+    const store = makeStore({
+      reports: { invoices: { date: {}, parameters: { format: 'excel' } } },
+    });
+    render(wrap(store, <InvoicesReportFormContainer />));
+    const ReportForm = require('../components/ReportForm').default;
+    const lastProps = ReportForm.mock.calls[ReportForm.mock.calls.length - 1][0];
+    expect(lastProps.format).toBe('excel');
+  });
+
+  it('InvoicesReportFormContainer dispatches SET_REPORT_PARAMETER when the format is changed', () => {
+    const store = makeStore({ reports: { invoices: { date: {}, parameters: {} } } });
+    render(wrap(store, <InvoicesReportFormContainer />));
+    const ReportForm = require('../components/ReportForm').default;
+    const lastProps = ReportForm.mock.calls[ReportForm.mock.calls.length - 1][0];
+
+    lastProps.setFormat('excel');
+
+    const paramActions = store.actions.filter(a => a.type === 'SET_REPORT_PARAMETER');
+    expect(paramActions).toHaveLength(1);
+    expect(paramActions[0].payload).toEqual({
+      report: 'invoices',
+      parameterName: 'format',
+      parameterValue: 'excel',
+    });
+  });
+
   it('AerodromeStatusBannerContainer dispatches WATCH_CURRENT_AERODROME_STATUS exactly once on mount', () => {
     const store = makeStore({
       settings: {
diff --git a/src/locales/de.json b/src/locales/de.json
index 30cf2376..31f47d84 100644
--- a/src/locales/de.json
+++ b/src/locales/de.json
@@ -432,7 +432,8 @@
   "report": {
     "year": "Jahr",
     "month": "Monat",
-    "delimiter": "Trennzeichen"
+    "delimiter": "Trennzeichen",
+    "format": "Format"
   },
   "yearlySummary": {
     "intro": "Die Jahreszusammenfassung enthält für jeden Monat des Jahres eine Zeile mit den folgenden Informationen:",
@@ -602,6 +603,9 @@
     "colEmail": "E-Mail",
     "colDirection": "Einflug / Ausflug",
     "directionArrival": "Einflug",
-    "directionDeparture": "Ausflug"
+    "directionDeparture": "Ausflug",
+    "formatPdf": "PDF",
+    "formatExcel": "Excel",
+    "sheetNameFallback": "Rechnungsempfänger"
   }
 }
diff --git a/src/locales/en.json b/src/locales/en.json
index 3ae5e976..391da19f 100644
--- a/src/locales/en.json
+++ b/src/locales/en.json
@@ -432,7 +432,8 @@
   "report": {
     "year": "Year",
     "month": "Month",
-    "delimiter": "Delimiter"
+    "delimiter": "Delimiter",
+    "format": "Format"
   },
   "yearlySummary": {
     "intro": "The yearly summary contains one row per month with the following information:",
@@ -602,6 +603,9 @@
     "colEmail": "Email",
     "colDirection": "Arrival / Departure",
     "directionArrival": "Arrival",
-    "directionDeparture": "Departure"
+    "directionDeparture": "Departure",
+    "formatPdf": "PDF",
+    "formatExcel": "Excel",
+    "sheetNameFallback": "Invoice recipient"
   }
 }
diff --git a/src/modules/reports/sagas.spec.ts b/src/modules/reports/sagas.spec.ts
index 9bfc3e09..2c639912 100644
--- a/src/modules/reports/sagas.spec.ts
+++ b/src/modules/reports/sagas.spec.ts
@@ -5,10 +5,13 @@ import * as sagas from './sagas';
 jest.mock('../../util/report', () => ({
   airstat: jest.fn(),
   invoices: jest.fn(),
+  invoicesExcel: jest.fn(),
   landings: jest.fn(),
   yearlySummary: jest.fn(),
 }));
 
+jest.mock('../../util/downloadBlob', () => jest.fn());
+
 describe('modules', () => {
   describe('reports', () => {
     describe('sagas', () => {
@@ -105,6 +108,134 @@ describe('modules', () => {
         });
       });
 
+      describe('generateReport (xlsx path - invoices)', () => {
+        it('should generate and download an xlsx report when format is excel', () => {
+          const report = 'invoices';
+          const action = actions.generateReport(report);
+          const generator = sagas.generateReport(action);
+
+          expect(generator.next().value).toEqual(
+            put(actions.setReportGenerationInProgress(report, true))
+          );
+
+          // select
+          generator.next();
+
+          const reportState = {
+            date: {year: 2024, month: 11},
+            parameters: {format: 'excel'}
+          };
+
+          const blob = {size: 1234};
+          const download = {
+            type: 'xlsx',
+            filename: 'invoice_recipients_2024_11.xlsx',
+            result: blob
+          };
+
+          expect(generator.next(reportState).value).toMatchObject({
+            type: 'CALL'
+          });
+
+          expect(generator.next(download).value).toEqual(
+            put(actions.setReportGenerationInProgress(report, false))
+          );
+
+          const downloadEffect = generator.next().value;
+          expect(downloadEffect).toMatchObject({type: 'CALL'});
+          expect((downloadEffect as any).payload.args).toEqual([
+            'invoice_recipients_2024_11.xlsx',
+            blob
+          ]);
+
+          expect(generator.next().done).toEqual(true);
+        });
+
+        it('drives the inner generator to an xlsx descriptor for format=excel', () => {
+          // The two tests above simulate generate()'s return value; this one
+          // actually runs generate()'s switch/case to the end, so the filename
+          // template and the excel/pdf branch choice are genuinely exercised.
+          const {invoices, invoicesExcel} = require('../../util/report');
+          const blob = {size: 1};
+          const generator = sagas.generateReport(actions.generateReport('invoices'));
+
+          generator.next();
+          generator.next();
+
+          const callEffect = generator.next({
+            date: {year: 2024, month: 11},
+            parameters: {format: 'excel'}
+          }).value;
+
+          const inner = (callEffect as any).payload.fn(
+            'invoices', 2024, 11, {format: 'excel'}
+          );
+          const innerCallEffect = inner.next().value;
+          expect(innerCallEffect.payload.fn).toBe(invoicesExcel);
+          expect(innerCallEffect.payload.args).toEqual([2024, 11, {format: 'excel'}]);
+
+          const {value: result, done} = inner.next(blob);
+          expect(done).toBe(true);
+          expect(result).toEqual({
+            type: 'xlsx',
+            filename: 'invoice_recipients_2024_11.xlsx',
+            result: blob
+          });
+          expect(invoices).not.toHaveBeenCalled();
+        });
+
+        it('drives the inner generator to a pdf descriptor when no format is set', () => {
+          const {invoices, invoicesExcel} = require('../../util/report');
+          const pdfResult = {download: jest.fn()};
+          const generator = sagas.generateReport(actions.generateReport('invoices'));
+
+          generator.next();
+          generator.next();
+
+          const callEffect = generator.next({
+            date: {year: 2024, month: 11},
+            parameters: {}
+          }).value;
+
+          const inner = (callEffect as any).payload.fn('invoices', 2024, 11, {});
+          const innerCallEffect = inner.next().value;
+          expect(innerCallEffect.payload.fn).toBe(invoices);
+
+          const {value: result, done} = inner.next(pdfResult);
+          expect(done).toBe(true);
+          expect(result).toEqual({
+            type: 'pdf',
+            filename: 'invoice_recipients_2024_11.pdf',
+            result: pdfResult
+          });
+          expect(invoicesExcel).not.toHaveBeenCalled();
+        });
+      });
+
+      describe('generateReport (failure)', () => {
+        it('clears the in-progress flag when generation fails', () => {
+          const report = 'invoices';
+          const generator = sagas.generateReport(actions.generateReport(report));
+
+          expect(generator.next().value).toEqual(
+            put(actions.setReportGenerationInProgress(report, true))
+          );
+
+          // select
+          generator.next();
+
+          // generate call
+          generator.next({date: {year: 2024, month: 11}, parameters: {format: 'excel'}});
+
+          // A failure must not leave the form disabled forever.
+          expect(generator.throw(new Error('customs down')).value).toEqual(
+            put(actions.setReportGenerationInProgress(report, false))
+          );
+
+          expect(() => generator.next()).toThrow('customs down');
+        });
+      });
+
       describe('generateReport (csv path - landings)', () => {
         it('should generate and download a landings csv report', () => {
           const report = 'landings';
diff --git a/src/modules/reports/sagas.ts b/src/modules/reports/sagas.ts
index ef7aefc3..f15ca810 100644
--- a/src/modules/reports/sagas.ts
+++ b/src/modules/reports/sagas.ts
@@ -1,6 +1,7 @@
 import {all, call, put, select, takeEvery} from 'redux-saga/effects';
 import * as actions from './actions';
-import {airstat, invoices, landings, yearlySummary} from '../../util/report';
+import {airstat, invoices, invoicesExcel, landings, yearlySummary} from '../../util/report';
+import downloadBlob from '../../util/downloadBlob';
 
 export const selectReport = (report: string) => (state: any) => state.reports[report];
 
@@ -16,6 +17,13 @@ function* generate(report: string, year: number, month: number, options: unknown
       const yearlySummaryResult = yield call(yearlySummary, year, options)
       return csv(yearlySummaryResult);
     case 'invoices':
+      if ((options as any)?.format === 'excel') {
+        const invoicesExcelResult = yield call(invoicesExcel, year, month, options)
+        return xlsx(
+          `invoice_recipients_${year}_${month}.xlsx`,
+          invoicesExcelResult
+        )
+      }
       const invoicesResult = yield call(invoices, year, month, options)
       return pdf(
         `invoice_recipients_${year}_${month}.pdf`,
@@ -41,6 +49,14 @@ function pdf(filename: string, result: unknown) {
   }
 }
 
+function xlsx(filename: string, result: unknown) {
+  return {
+    type: 'xlsx',
+    filename,
+    result
+  }
+}
+
 function* startDownload(download: any) {
   download.start();
 }
@@ -55,14 +71,20 @@ export function* generateReport(action: any) {
   const year = state.date.year;
   const month = state.date.month;
 
-  const download = yield call(generate, report, year, month, state.parameters);
-
-  yield put(actions.setReportGenerationInProgress(report, false));
+  let download;
+  try {
+    download = yield call(generate, report, year, month, state.parameters);
+  } finally {
+    // Always clear the flag: a failed report must not leave the form disabled.
+    yield put(actions.setReportGenerationInProgress(report, false));
+  }
 
   if (download.type === 'csv') {
     yield call(startDownload, download.result);
   } else if (download.type === 'pdf') {
     download.result.download(download.filename)
+  } else if (download.type === 'xlsx') {
+    yield call(downloadBlob, download.filename, download.result)
   } else {
     throw new Error('Unsupported type ' + download.type)
   }
diff --git a/src/util/InvoicesExcelReport.spec.ts b/src/util/InvoicesExcelReport.spec.ts
new file mode 100644
index 00000000..5b84cd38
--- /dev/null
+++ b/src/util/InvoicesExcelReport.spec.ts
@@ -0,0 +1,533 @@
+// A non-UTC timezone, so that any local-time arithmetic in the date handling
+// would show up as an off-by-one day rather than passing by coincidence.
+process.env.TZ = 'America/New_York';
+
+describe('util', () => {
+  describe('InvoicesExcelReport', () => {
+    let InvoicesExcelReport;
+    let sanitizeSheetName;
+    let columnLetter;
+    let toDateValue;
+
+    beforeEach(() => {
+      global.__CONF__ = {
+        aerodrome: {
+          ICAO: 'LSZT',
+          runways: [
+            {name: '10', type: 'A'},
+            {name: '28', type: 'A'},
+          ],
+        },
+        enabledFlightTypes: {0: 'private', 1: 'instruction'},
+        memberManagement: false,
+      };
+
+      jest.resetModules();
+      jest.mock('./firebase');
+      jest.mock('firebase/database', () => ({
+        get: jest.fn(),
+        query: jest.fn(ref => ref),
+        orderByChild: jest.fn(),
+        startAt: jest.fn(),
+        endAt: jest.fn(),
+      }));
+
+      const module = require('./InvoicesExcelReport');
+      InvoicesExcelReport = module.default;
+      sanitizeSheetName = module.sanitizeSheetName;
+      columnLetter = module.columnLetter;
+      toDateValue = module.toDateValue;
+    });
+
+    const makeReport = (year = 2023, month = 6, options = {}) =>
+      new InvoicesExcelReport(year, month, options);
+
+    const arrival = (overrides = {}) => Object.assign({
+      date: '2023-06-01',
+      time: '10:00',
+      immatriculation: 'HB-KOF',
+      mtow: 750,
+      firstname: 'Max',
+      lastname: 'Muster',
+      email: 'max@example.com',
+      flightType: 'private',
+      feeTotalNet: 10,
+      feeVat: 1,
+      feeRoundingDifference: 0,
+      feeTotalGross: 11,
+    }, overrides);
+
+    const declaration = (overrides = {}) => Object.assign({
+      date: '2023-06-01',
+      registration: 'HB-KOF',
+      email: 'max@example.com',
+      direction: 'arrival',
+      fee: {totalNet: 10, vat: 1, roundingDifference: 0, totalGrossRounded: 11},
+    }, overrides);
+
+    let lastBuffer: any = null;
+
+    /**
+     * Render the sheets to a real xlsx buffer and read it back, so assertions
+     * are made against what actually lands in the file.
+     */
+    async function render(report, recipientNames, arrivalRecipients = {}, customsRecipients = {}) {
+      const {Workbook} = require('exceljs');
+      const workbook = new Workbook();
+      workbook.calcProperties.fullCalcOnLoad = true;
+
+      report.addSheets(workbook, recipientNames, arrivalRecipients, customsRecipients);
+
+      lastBuffer = await workbook.xlsx.writeBuffer();
+      const reloaded = new Workbook();
+      await reloaded.xlsx.load(lastBuffer);
+      return reloaded;
+    }
+
+    /**
+     * The formula cells of a rendered sheet, read straight out of the xlsx XML.
+     *
+     * exceljs's own reader reports a cached result of 0 as undefined, which
+     * would hide whether zero totals actually reach the file — and a zero total
+     * read as blank is exactly the failure the cached results exist to prevent.
+     */
+    async function writtenFormulas(sheetIndex = 1) {
+      const JSZip = require('jszip');
+      const zip = await JSZip.loadAsync(lastBuffer);
+      const xml = await zip.file(`xl/worksheets/sheet${sheetIndex}.xml`).async('string');
+
+      const cells: any[] = [];
+      const pattern = /<c r="([A-Z]+\d+)"[^>]*><f>([^<]*)<\/f><v>([^<]*)<\/v><\/c>/g;
+      let match;
+      while ((match = pattern.exec(xml)) !== null) {
+        cells.push({ref: match[1], formula: match[2], result: Number(match[3])});
+      }
+      return cells;
+    }
+
+    /** The row whose first cell matches the given text. */
+    function rowStartingWith(sheet, text) {
+      let found: any = null;
+      sheet.eachRow(row => {
+        if (!found && row.getCell(1).value === text) {
+          found = row;
+        }
+      });
+      return found;
+    }
+
+    describe('columnLetter', () => {
+      it('maps the first columns to A, B, C', () => {
+        expect(columnLetter(1)).toBe('A');
+        expect(columnLetter(2)).toBe('B');
+        expect(columnLetter(3)).toBe('C');
+      });
+
+      it('maps the last landing fee column to L', () => {
+        expect(columnLetter(12)).toBe('L');
+      });
+
+      it('rolls over past Z', () => {
+        expect(columnLetter(26)).toBe('Z');
+        expect(columnLetter(27)).toBe('AA');
+        expect(columnLetter(28)).toBe('AB');
+      });
+    });
+
+    describe('toDateValue', () => {
+      it('converts a local date string to a UTC date', () => {
+        const value = toDateValue('2023-06-01');
+        expect(value).toBeInstanceOf(Date);
+        expect(value.getUTCFullYear()).toBe(2023);
+        expect(value.getUTCMonth()).toBe(5);
+        expect(value.getUTCDate()).toBe(1);
+      });
+
+      it('passes through values that are not plain local dates', () => {
+        expect(toDateValue('2023-06-01T10:00:00Z')).toBe('2023-06-01T10:00:00Z');
+        expect(toDateValue(undefined)).toBeUndefined();
+        expect(toDateValue(42)).toBe(42);
+      });
+    });
+
+    describe('sanitizeSheetName', () => {
+      it('keeps an ordinary name unchanged', () => {
+        expect(sanitizeSheetName('Company A')).toBe('Company A');
+      });
+
+      it('replaces the characters Excel forbids', () => {
+        expect(sanitizeSheetName('A/B:C*D?E[F]G\\H')).toBe('A B C D E F G H');
+      });
+
+      it('truncates to 31 characters', () => {
+        const name = sanitizeSheetName('x'.repeat(50));
+        expect(name).toHaveLength(31);
+      });
+
+      it('falls back when the name is empty after cleaning', () => {
+        expect(sanitizeSheetName('///')).toBe('Rechnungsempfänger');
+        expect(sanitizeSheetName('')).toBe('Rechnungsempfänger');
+      });
+
+      it('de-duplicates against names already used', () => {
+        expect(sanitizeSheetName('Company A', ['Company A'])).toBe('Company A (2)');
+        expect(sanitizeSheetName('Company A', ['Company A', 'Company A (2)']))
+          .toBe('Company A (3)');
+      });
+
+      it('keeps a de-duplicated long name within the length limit', () => {
+        const base = sanitizeSheetName('y'.repeat(50));
+        const name = sanitizeSheetName('y'.repeat(50), [base]);
+        expect(name.length).toBeLessThanOrEqual(31);
+        expect(name.endsWith(' (2)')).toBe(true);
+      });
+
+      it('de-duplicates case-insensitively, as Excel does', () => {
+        // exceljs rejects names differing only in case, which would abort the
+        // whole report.
+        expect(sanitizeSheetName('flugschule ag', ['Flugschule AG']))
+          .toBe('flugschule ag (2)');
+      });
+
+      it('strips leading and trailing single quotes', () => {
+        expect(sanitizeSheetName("'Air Service'")).toBe('Air Service');
+      });
+
+      it('strips a quote that was already at the edge before truncation', () => {
+        const name = sanitizeSheetName('x'.repeat(30) + "''''");
+        expect(name.endsWith("'")).toBe(false);
+      });
+
+      it('strips a quote that truncation newly exposes at the edge', () => {
+        // The quote sits mid-string in the original name, so the first trim
+        // pass leaves it alone; only cutting at 31 chars lands exactly on it.
+        const name = 'x'.repeat(30) + "'" + 'y'.repeat(5);
+        expect(name.length).toBeGreaterThan(31);
+        expect(name.substring(0, 31).endsWith("'")).toBe(true);
+
+        const result = sanitizeSheetName(name);
+        expect(result.endsWith("'")).toBe(false);
+      });
+
+      it('avoids the reserved name History', () => {
+        expect(sanitizeSheetName('History')).not.toBe('History');
+      });
+
+      it('falls back for a nullish name', () => {
+        expect(sanitizeSheetName(null as any)).toBe('Rechnungsempfänger');
+        expect(sanitizeSheetName(undefined as any)).toBe('Rechnungsempfänger');
+      });
+
+      it('falls back when the cleaned name survives but collapses to nothing after the final quote trim', () => {
+        // The forbidden-character strip leaves the surrounding spaces alone (a
+        // quote is not a forbidden character), so the first trim only removes
+        // whitespace and 'cleaned' comes out as a lone quote — non-empty, so
+        // the fallback used while building 'base' is skipped. Only the very
+        // last trim (after substring) reduces it to '', which is what the
+        // final `|| fallback` exists to catch.
+        expect(sanitizeSheetName("  '  ")).toBe('Rechnungsempfänger');
+      });
+
+      it('distinguishes names that collide only after truncation', () => {
+        const first = sanitizeSheetName('z'.repeat(31) + 'AAA');
+        const second = sanitizeSheetName('z'.repeat(31) + 'BBB', [first]);
+        expect(second).not.toBe(first);
+      });
+    });
+
+    describe('addSheets', () => {
+      it('adds one sheet per recipient, in the given order', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Online-Zahlungen', 'Company A'], {
+          'Company A': [arrival()],
+        });
+        expect(workbook.worksheets.map(sheet => sheet.name))
+          .toEqual(['Online-Zahlungen', 'Company A']);
+      });
+
+      it('titles each sheet with the recipient and month', async () => {
+        const report = makeReport(2023, 6);
+        const workbook = await render(report, ['Company A'], {'Company A': [arrival()]});
+        expect(workbook.getWorksheet('Company A').getCell('A1').value)
+          .toBe('Company A (Juni 2023)');
+      });
+
+      it('uses the untruncated recipient name in the title even when the sheet name is cut', async () => {
+        const longName = 'A very long invoice recipient name indeed';
+        const report = makeReport();
+        const workbook = await render(report, [longName], {[longName]: [arrival()]});
+        const sheet = workbook.worksheets[0];
+        expect(sheet.name.length).toBeLessThanOrEqual(31);
+        expect(sheet.getCell('A1').value).toContain(longName);
+      });
+
+      it('gives colliding recipient names distinct sheets', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['A/B', 'A:B'], {
+          'A/B': [arrival()],
+          'A:B': [arrival()],
+        });
+        const names = workbook.worksheets.map(sheet => sheet.name);
+        expect(new Set(names).size).toBe(2);
+      });
+
+      it('survives recipient names that Excel would reject', async () => {
+        // Recipient names are user-controlled; any of these makes exceljs throw
+        // if it reaches addWorksheet unsanitised, which would abort the report.
+        const names = [
+          'History',
+          "'Air Service'",
+          'Flugschule AG',
+          'flugschule ag',
+          'A/B:C*D?E[F]',
+          'A very long invoice recipient name that goes on and on',
+          '',
+        ];
+        const report = makeReport();
+        const arrivalRecipients = {};
+        names.forEach(name => { arrivalRecipients[name] = [arrival()]; });
+
+        const workbook = await render(report, names, arrivalRecipients);
+
+        const sheetNames = workbook.worksheets.map(sheet => sheet.name);
+        expect(sheetNames).toHaveLength(names.length);
+        expect(new Set(sheetNames.map(n => n.toLowerCase())).size).toBe(names.length);
+        sheetNames.forEach(name => {
+          expect(name.length).toBeLessThanOrEqual(31);
+          expect(name).not.toBe('History');
+          expect(/[[\]:*?/\\]/.test(name)).toBe(false);
+          expect(/(^')|('$)/.test(name)).toBe(false);
+        });
+      });
+
+      it('writes a fallback sheet with the no-recipients message', async () => {
+        const report = makeReport(2023, 6);
+        const workbook = await render(report, []);
+        expect(workbook.worksheets).toHaveLength(1);
+        expect(workbook.worksheets[0].getCell('A1').value)
+          .toContain('Keine Rechnungsempfänger');
+      });
+
+      it('still adds a sheet for a recipient with no rows', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Online-Zahlungen']);
+        expect(workbook.worksheets.map(sheet => sheet.name)).toEqual(['Online-Zahlungen']);
+        expect(await writtenFormulas()).toHaveLength(0);
+      });
+    });
+
+    describe('landing fees table', () => {
+      it('writes amounts as numbers, not formatted strings', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {
+          'Company A': [arrival({feeTotalNet: 14.5, feeVat: 1.2, feeRoundingDifference: 0.3, feeTotalGross: 16})],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+        const dataRow = sheet.getRow(5);
+        expect(typeof dataRow.getCell(9).value).toBe('number');
+        expect(dataRow.getCell(9).value).toBe(14.5);
+        expect(dataRow.getCell(12).value).toBe(16);
+        expect(dataRow.getCell(12).numFmt).toBe('#,##0.00');
+      });
+
+      it('writes the date as a real date on the intended calendar day', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {
+          'Company A': [arrival({date: '2023-06-01'})],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+        const dateCell = sheet.getRow(5).getCell(1);
+        expect(dateCell.value).toBeInstanceOf(Date);
+        expect(dateCell.value.toISOString().substring(0, 10)).toBe('2023-06-01');
+      });
+
+      it('totals each amount column with a SUM formula carrying a cached result', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {
+          'Company A': [
+            arrival({feeTotalNet: 10, feeVat: 1, feeRoundingDifference: 0, feeTotalGross: 11}),
+            arrival({feeTotalNet: 20, feeVat: 2, feeRoundingDifference: 0, feeTotalGross: 22}),
+          ],
+        });
+        const totals = await writtenFormulas();
+
+        expect(totals).toHaveLength(4);
+        expect(totals.map(cell => cell.result)).toEqual([30, 3, 0, 33]);
+        totals.forEach(cell => {
+          expect(cell.formula).toMatch(/^SUM\([A-Z]+\d+:[A-Z]+\d+\)$/);
+        });
+      });
+
+      it('sums exactly the rows of its own table', async () => {
+        const report = makeReport();
+        await render(report, ['Company A'], {
+          'Company A': [arrival(), arrival()],
+        });
+        // Title (1), spacer (2), subheader (3), header (4), two data rows (5-6).
+        expect((await writtenFormulas())[0].formula).toBe('SUM(I5:I6)');
+      });
+
+      it('leaves net, VAT and rounding empty for transition-month rows', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {
+          'Company A': [arrival({
+            feeTotalNet: undefined,
+            feeVat: undefined,
+            feeRoundingDifference: undefined,
+            feeTotalGross: undefined,
+            landingFeeTotal: 20,
+          })],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+        const dataRow = sheet.getRow(5);
+
+        expect(dataRow.getCell(9).value).toBeNull();
+        expect(dataRow.getCell(10).value).toBeNull();
+        expect(dataRow.getCell(11).value).toBeNull();
+        expect(dataRow.getCell(12).value).toBe(20);
+      });
+
+      it('keeps cached totals consistent with SUM over blanks in the transition month', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {
+          'Company A': [
+            arrival({
+              feeTotalNet: undefined, feeVat: undefined,
+              feeRoundingDifference: undefined, feeTotalGross: undefined,
+              landingFeeTotal: 20,
+            }),
+            arrival({feeTotalNet: 10, feeVat: 1, feeRoundingDifference: 0, feeTotalGross: 11}),
+          ],
+        });
+        const totals = await writtenFormulas();
+        // SUM ignores the blank cells, matching the JS accumulation exactly.
+        expect(totals.map(cell => cell.result)).toEqual([10, 1, 0, 31]);
+      });
+    });
+
+    describe('malformed amounts', () => {
+      it('writes no total at all rather than NaN when an amount is missing', async () => {
+        const report = makeReport();
+        await render(report, ['Company A'], {
+          'Company A': [arrival({
+            feeTotalNet: undefined, feeVat: undefined,
+            feeRoundingDifference: undefined, feeTotalGross: undefined,
+            landingFeeTotal: undefined,
+          })],
+        });
+        const totals = await writtenFormulas();
+        // A NaN here would make Excel report the workbook as corrupt.
+        totals.forEach(cell => expect(Number.isNaN(cell.result)).toBe(false));
+        expect(totals.map(cell => cell.result)).toEqual([0, 0, 0, 0]);
+      });
+
+      it('does not let one malformed row poison the column total', async () => {
+        const report = makeReport();
+        await render(report, ['Company A'], {
+          'Company A': [
+            arrival({feeTotalGross: undefined, landingFeeTotal: undefined}),
+            arrival({feeTotalNet: 10, feeVat: 1, feeRoundingDifference: 0, feeTotalGross: 11}),
+          ],
+        });
+        expect((await writtenFormulas()).map(cell => cell.result)).toEqual([10, 1, 0, 11]);
+      });
+
+      it('survives a customs declaration with no fee', async () => {
+        const report = makeReport();
+        await render(report, ['Company A'], {}, {
+          'Company A': [declaration({fee: undefined})],
+        });
+        expect((await writtenFormulas()).map(cell => cell.result)).toEqual([0, 0, 0, 0]);
+      });
+    });
+
+    describe('customs fees tables', () => {
+      it('writes cancelled and non-cancelled declarations to separate tables', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {}, {
+          'Company A': [declaration(), declaration({cancelled: true})],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+
+        expect(rowStartingWith(sheet, 'Zollgebühren')).not.toBeNull();
+        expect(rowStartingWith(sheet, 'Zollgebühren ANNULLIERT')).not.toBeNull();
+        // Four total columns per table, two tables.
+        expect(await writtenFormulas()).toHaveLength(8);
+      });
+
+      it('omits the cancelled table when nothing is cancelled', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {}, {
+          'Company A': [declaration()],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+        expect(rowStartingWith(sheet, 'Zollgebühren ANNULLIERT')).toBeNull();
+        expect(await writtenFormulas()).toHaveLength(4);
+      });
+
+      it('handles a numeric fee as a transition-month fallback', async () => {
+        const report = makeReport();
+        await render(report, ['Company A'], {}, {
+          'Company A': [declaration({fee: 15})],
+        });
+        const totals = await writtenFormulas();
+        expect(totals.map(cell => cell.result)).toEqual([0, 0, 0, 15]);
+      });
+
+      it('translates the direction', async () => {
+        const report = makeReport();
+        const workbook = await render(report, ['Company A'], {}, {
+          'Company A': [declaration({direction: 'departure'})],
+        });
+        const sheet = workbook.getWorksheet('Company A');
+        expect(sheet.getRow(5).getCell(4).value).toBe('Ausflug');
+      });
+    });
+
+    describe('build', () => {
+      it('resolves with an xlsx blob', async () => {
+        const report = makeReport();
+        const blob = await report.build({
+          recipientNames: ['Company A'],
+          arrivalRecipients: {'Company A': [arrival()]},
+          customsRecipients: {},
+        });
+        expect(blob).toBeInstanceOf(Blob);
+        expect(blob.type)
+          .toBe('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
+        expect(blob.size).toBeGreaterThan(0);
+      });
+
+      it('marks the workbook for full recalculation on load', async () => {
+        const {Workbook} = require('exceljs');
+        const report = makeReport();
+        const workbook = new Workbook();
+        workbook.calcProperties.fullCalcOnLoad = true;
+        report.addSheets(workbook, ['Company A'], {'Company A': [arrival()]}, {});
+        expect(workbook.calcProperties.fullCalcOnLoad).toBe(true);
+      });
+    });
+
+    describe('generate', () => {
+      it('resolves with the blob once the data is collected', async () => {
+        const report = makeReport();
+        report.collect = jest.fn().mockResolvedValue({
+          recipientNames: ['Company A'],
+          arrivalRecipients: {'Company A': [arrival()]},
+          customsRecipients: {},
+        });
+
+        await expect(report.generate()).resolves.toBeInstanceOf(Blob);
+      });
+
+      it('rejects when the data cannot be collected', async () => {
+        const report = makeReport();
+        report.collect = jest.fn().mockRejectedValue(new Error('customs down'));
+
+        // A silently swallowed failure would leave the form stuck showing the
+        // report as still being generated.
+        await expect(report.generate()).rejects.toThrow('customs down');
+      });
+    });
+  });
+});
diff --git a/src/util/InvoicesExcelReport.ts b/src/util/InvoicesExcelReport.ts
new file mode 100644
index 00000000..18efeb7a
--- /dev/null
+++ b/src/util/InvoicesExcelReport.ts
@@ -0,0 +1,360 @@
+import InvoicesReportData from './InvoicesReportData';
+import dates from '../util/dates';
+import {getLabel as getFlightTypeLabel} from '../util/flightTypes';
+import i18n from '../i18n';
+import loadWorkbookConstructor from './loadExcelJs';
+
+const t = i18n.getFixedT('de');
+
+export const XLSX_MIME_TYPE =
+  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
+
+const MONEY_FORMAT = '#,##0.00';
+const DATE_FORMAT = 'dd.mm.yyyy';
+
+// Excel rejects these characters in worksheet names and caps them at 31 chars.
+const FORBIDDEN_SHEET_NAME_CHARS = /[[\]:*?/\\]/g;
+const MAX_SHEET_NAME_LENGTH = 31;
+// A worksheet name may not start or end with a single quote, and 'History' is
+// reserved. exceljs throws on all of these, which would abort the whole report.
+const EDGE_QUOTES = /^'+|'+$/g;
+const RESERVED_SHEET_NAME = 'History';
+
+const LOCAL_DATE_PATTERN = /^(\d{4})-(\d{2})-(\d{2})$/;
+
+interface Column {
+  header: string;
+  width: number;
+  numFmt?: string;
+  /** Whether the table's totals row sums this column. */
+  total?: boolean;
+}
+
+/**
+ * Convert a 1-based column index to its spreadsheet letter (1 -> A, 27 -> AA).
+ */
+export const columnLetter = (index: number): string => {
+  let letter = '';
+  let remaining = index;
+  while (remaining > 0) {
+    letter = String.fromCharCode(65 + ((remaining - 1) % 26)) + letter;
+    remaining = Math.floor((remaining - 1) / 26);
+  }
+  return letter;
+};
+
+/**
+ * Turn a local `YYYY-MM-DD` date into a real date cell value. Built in UTC so
+ * the writer's timezone can never shift it onto the neighbouring day. Anything
+ * that is not a plain local date is passed through as-is.
+ */
+export const toDateValue = (localDate: any): any => {
+  if (typeof localDate !== 'string') {
+    return localDate;
+  }
+  const match = LOCAL_DATE_PATTERN.exec(localDate);
+  if (!match) {
+    return localDate;
+  }
+  const [, year, month, day] = match;
+  return new Date(Date.UTC(Number(year), Number(month) - 1, Number(day)));
+};
+
+/**
+ * Make a recipient name usable as a worksheet name: drop the characters Excel
+ * forbids, keep it within the length limit, and disambiguate against the names
+ * already used in this workbook. Recipient names are user-controlled, so none
+ * of these can be assumed away.
+ */
+export const sanitizeSheetName = (name: string, usedNames: string[] = []): string => {
+  const trim = (value: string) => value.replace(EDGE_QUOTES, '').trim();
+
+  const cleaned = trim(
+    String(name == null ? '' : name).replace(FORBIDDEN_SHEET_NAME_CHARS, ' ')
+  );
+
+  // Truncating can expose a new trailing quote, so trim again afterwards.
+  const base = trim(
+    (cleaned || t('invoicesReport.sheetNameFallback')).substring(0, MAX_SHEET_NAME_LENGTH)
+  ) || t('invoicesReport.sheetNameFallback');
+
+  // exceljs compares worksheet names case-insensitively, so the check has to.
+  const isTaken = (candidate: string) =>
+    candidate === RESERVED_SHEET_NAME ||
+    usedNames.some(used => used.toLowerCase() === candidate.toLowerCase());
+
+  if (!isTaken(base)) {
+    return base;
+  }
+
+  for (let counter = 2; ; counter++) {
+    const suffix = ` (${counter})`;
+    const candidate =
+      base.substring(0, MAX_SHEET_NAME_LENGTH - suffix.length).trim() + suffix;
+    if (!isTaken(candidate)) {
+      return candidate;
+    }
+  }
+};
+
+/**
+ * Amounts reach a numeric cell verbatim, so anything that is not a finite
+ * number becomes an empty cell instead. A NaN would otherwise be written as
+ * `<v>NaN</v>`, which Excel reports as a corrupt workbook, and a single bad row
+ * would poison its column's total.
+ */
+const toAmount = (value: any): number | null =>
+  typeof value === 'number' && isFinite(value) ? value : null;
+
+const addAmounts = (totals: number[], amounts: (number | null)[]) => {
+  amounts.forEach((amount, index) => {
+    if (amount !== null) {
+      totals[index] += amount;
+    }
+  });
+};
+
+/**
+ * The invoice recipient report as an Excel workbook: one worksheet per
+ * recipient, mirroring the one-page-per-recipient layout of the PDF version.
+ *
+ * Unlike the PDF, amounts are written as real numbers and every totals row is a
+ * SUM formula, so recipients can filter, correct and re-sum rows in place. Each
+ * formula also carries its computed result as a cached value, because tools
+ * that do not evaluate formulas (pandas/openpyxl read with `data_only=True`)
+ * otherwise read those cells as empty.
+ */
+class InvoicesExcelReport extends InvoicesReportData {
+
+  /**
+   * Resolves with the workbook as a blob. Rejections propagate to the caller so
+   * a failure cannot leave the report stuck as "in progress".
+   */
+  generate(): Promise<Blob> {
+    return this.collect().then(data => this.build(data));
+  }
+
+  async build({recipientNames, arrivalRecipients, customsRecipients}) {
+    const Workbook = await loadWorkbookConstructor();
+
+    const workbook = new Workbook();
+    workbook.created = this.creationDate.toDate();
+    // Recalculate on open so the totals can never be shown from a stale cache.
+    workbook.calcProperties.fullCalcOnLoad = true;
+
+    this.addSheets(workbook, recipientNames, arrivalRecipients, customsRecipients);
+
+    const buffer = await workbook.xlsx.writeBuffer();
+
+    return new Blob([buffer], {type: XLSX_MIME_TYPE});
+  }
+
+  addSheets(workbook, recipientNames, arrivalRecipients, customsRecipients) {
+    if (recipientNames.length === 0) {
+      const sheet = workbook.addWorksheet(t('invoicesReport.sheetNameFallback'));
+      sheet.addRow([t('invoicesReport.noRecipients', {month: this.getMonthLabel()})]);
+      return;
+    }
+
+    const monthLabel = this.getMonthLabel();
+    const usedSheetNames: string[] = [];
+
+    recipientNames.forEach(recipientName => {
+      const sheetName = sanitizeSheetName(recipientName, usedSheetNames);
+      usedSheetNames.push(sheetName);
+
+      const sheet = workbook.addWorksheet(sheetName);
+
+      const titleRow = sheet.addRow([`${recipientName} (${monthLabel})`]);
+      titleRow.getCell(1).font = {bold: true, size: 14};
+
+      this.addLandingFeesTable(sheet, arrivalRecipients[recipientName]);
+      this.addCustomsFeesTable(sheet, customsRecipients[recipientName], false);
+      this.addCustomsFeesTable(sheet, customsRecipients[recipientName], true);
+    });
+  }
+
+  landingFeeColumns(): Column[] {
+    return [
+      {header: t('invoicesReport.colDate'), width: 12, numFmt: DATE_FORMAT},
+      {header: t('invoicesReport.colTime'), width: 8},
+      {header: t('invoicesReport.colImmatriculation'), width: 15},
+      {header: 'MTOW', width: 8},
+      {header: t('invoicesReport.colFirstname'), width: 16},
+      {header: t('invoicesReport.colLastname'), width: 16},
+      {header: t('invoicesReport.colEmail'), width: 30},
+      {header: t('invoicesReport.colFlightType'), width: 18},
+      {header: t('invoicesReport.colSubtotal'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colVat'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colRounding'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colTotal'), width: 12, numFmt: MONEY_FORMAT, total: true},
+    ];
+  }
+
+  customsFeeColumns(): Column[] {
+    return [
+      {header: t('invoicesReport.colDate'), width: 12, numFmt: DATE_FORMAT},
+      {header: t('invoicesReport.colImmatriculation'), width: 15},
+      {header: t('invoicesReport.colEmail'), width: 30},
+      {header: t('invoicesReport.colDirection'), width: 18},
+      {header: t('invoicesReport.colSubtotal'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colVat'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colRounding'), width: 12, numFmt: MONEY_FORMAT, total: true},
+      {header: t('invoicesReport.colTotal'), width: 12, numFmt: MONEY_FORMAT, total: true},
+    ];
+  }
+
+  addLandingFeesTable(sheet, arrivals) {
+    if (!arrivals || arrivals.length === 0) {
+      return;
+    }
+
+    const totals = [0, 0, 0, 0];
+
+    const rows = arrivals.map(arrival => {
+      const {
+        date,
+        time,
+        immatriculation,
+        mtow,
+        firstname,
+        lastname,
+        email,
+        flightType,
+        feeTotalNet,
+        feeVat,
+        feeRoundingDifference,
+        feeTotalGross,
+        landingFeeTotal // fallback only for the "transition" month
+      } = arrival;
+
+      const amounts = typeof feeTotalGross === 'number'
+        ? [
+          toAmount(feeTotalNet),
+          toAmount(feeVat),
+          toAmount(feeRoundingDifference),
+          toAmount(feeTotalGross)
+        ]
+        // fallback only for the "transition" month
+        : [null, null, null, toAmount(landingFeeTotal)];
+
+      addAmounts(totals, amounts);
+
+      return [
+        toDateValue(date),
+        dates.formatTime(date, time),
+        immatriculation,
+        mtow,
+        firstname,
+        lastname,
+        email,
+        getFlightTypeLabel(flightType),
+        ...amounts
+      ];
+    });
+
+    this.addTable(sheet, t('invoicesReport.landingFees'), this.landingFeeColumns(), rows, totals);
+  }
+
+  addCustomsFeesTable(sheet, customsDeclarations, cancelled) {
+    const relevantDeclarations = customsDeclarations ? customsDeclarations
+      .filter(declaration => cancelled ? declaration.cancelled === true : declaration.cancelled !== true)
+      : [];
+
+    if (relevantDeclarations.length === 0) {
+      return;
+    }
+
+    const totals = [0, 0, 0, 0];
+
+    const rows = relevantDeclarations.map(declaration => {
+      const {date, direction, registration, email, fee} = declaration;
+
+      const amounts = typeof fee === 'number'
+        // fallback only for the "transition" month
+        ? [null, null, null, toAmount(fee)]
+        : [
+          toAmount(fee && fee.totalNet),
+          toAmount(fee && fee.vat),
+          toAmount(fee && fee.roundingDifference),
+          toAmount(fee && fee.totalGrossRounded)
+        ];
+
+      addAmounts(totals, amounts);
+
+      return [
+        toDateValue(date),
+        registration,
+        email,
+        direction === 'arrival'
+          ? t('invoicesReport.directionArrival')
+          : t('invoicesReport.directionDeparture'),
+        ...amounts
+      ];
+    });
+
+    const subHeader = cancelled
+      ? t('invoicesReport.customsFeesCancelled')
+      : t('invoicesReport.customsFees');
+
+    this.addTable(sheet, subHeader, this.customsFeeColumns(), rows, totals);
+  }
+
+  /**
+   * Append a titled table to a sheet: a subheader, a bold header row, the data
+   * rows, and a totals row of SUM formulas over just this table's rows.
+   *
+   * @param totals the JS sums, in order of the columns flagged `total`. They are
+   *   written as each formula's cached result.
+   */
+  addTable(sheet, subHeader: string, columns: Column[], rows: any[][], totals: number[]) {
+    sheet.addRow([]);
+
+    const subHeaderRow = sheet.addRow([subHeader]);
+    subHeaderRow.getCell(1).font = {bold: true, size: 12};
+
+    const headerRow = sheet.addRow(columns.map(column => column.header));
+    headerRow.font = {bold: true};
+
+    const firstDataRowNumber = headerRow.number + 1;
+
+    rows.forEach(values => {
+      const row = sheet.addRow(values);
+      columns.forEach((column, index) => {
+        if (column.numFmt) {
+          row.getCell(index + 1).numFmt = column.numFmt;
+        }
+      });
+    });
+
+    const lastDataRowNumber = firstDataRowNumber + rows.length - 1;
+
+    const totalsRow = sheet.addRow([]);
+    let totalIndex = 0;
+    columns.forEach((column, index) => {
+      if (!column.total) {
+        return;
+      }
+      const letter = columnLetter(index + 1);
+      const cell = totalsRow.getCell(index + 1);
+      // The cached result keeps the total readable by tools that do not
+      // evaluate formulas; without it they see an empty cell.
+      cell.value = {
+        formula: `SUM(${letter}${firstDataRowNumber}:${letter}${lastDataRowNumber})`,
+        result: totals[totalIndex]
+      };
+      cell.numFmt = column.numFmt;
+      cell.font = {bold: true};
+      totalIndex++;
+    });
+
+    columns.forEach((column, index) => {
+      const sheetColumn = sheet.getColumn(index + 1);
+      if (!sheetColumn.width || sheetColumn.width < column.width) {
+        sheetColumn.width = column.width;
+      }
+    });
+  }
+}
+
+export default InvoicesExcelReport;
diff --git a/src/util/InvoicesReport.ts b/src/util/InvoicesReport.ts
index 840a240f..e3c7a4d4 100644
--- a/src/util/InvoicesReport.ts
+++ b/src/util/InvoicesReport.ts
@@ -1,6 +1,4 @@
-import firebase, {getIdToken} from './firebase';
-import {get, query, orderByChild, startAt, endAt} from 'firebase/database';
-import {firebaseToLocal} from './movements';
+import InvoicesReportData from './InvoicesReportData';
 import dates from '../util/dates';
 import {getLabel as getFlightTypeLabel} from '../util/flightTypes';
 import formatMoney from './formatMoney'
@@ -8,45 +6,12 @@ import i18n from '../i18n';
 
 const t = i18n.getFixedT('de');
 
-import moment from 'moment';
-
 import pdfMake from 'pdfmake/build/pdfmake';
 import pdfFonts from 'pdfmake/build/vfs_fonts';
 
 (window as any).pdfFonts = pdfFonts; // actually not necessary, but otherwise `pdfFonts` is unused and would be removed
 
-class InvoicesReport {
-
-  get checkoutRecipientName() {
-    return t('invoicesReport.onlinePayments');
-  }
-
-  get cashRecipientName() {
-    return t('invoicesReport.cashPayments');
-  }
-
-
-  year: number;
-  month: number;
-  startDate: string;
-  endDate: string;
-  creationDate: any;
-  options: any;
-
-  constructor(year, month, options = {}) {
-    const monthStr = (month < 10 ? '0' : '') + month
-    const day = '01';
-
-    this.year = year
-    this.month = month
-
-    this.startDate = year + '-' + monthStr + '-' + day;
-    this.endDate = moment(this.startDate).endOf('month').format('YYYY-MM-DD');
-
-    this.creationDate = moment();
-
-    this.options = options;
-  }
+class InvoicesReport extends InvoicesReportData {
 
   generate(callback) {
     Promise.all([
@@ -58,40 +23,6 @@ class InvoicesReport {
     });
   }
 
-  readArrivals() {
-    return get(query(
-      firebase('/arrivals'),
-      orderByChild('dateTime'),
-      startAt(dates.isoStartOfDay(this.startDate)),
-      endAt(dates.isoEndOfDay(this.endDate))
-    ));
-  }
-
-  async fetchCustomsData(endpoint) {
-    const idToken = await getIdToken()
-    const url = `https://europe-west1-${__FIREBASE_PROJECT_ID__}.cloudfunctions.net/api/customs/${endpoint}?year=${this.year}&month=${this.month}`
-    const response = await fetch(url, {
-      headers: {
-        'Authorization': `Bearer ${idToken}`
-      }
-    })
-
-    if (!response.ok) {
-      console.log(`Failed to fetch customs ${endpoint}`, response)
-      throw new Error(`Failed to fetch customs ${endpoint}`)
-    }
-
-    return await response.json()
-  }
-
-  async readCustomsDeclarationsInvoices() {
-    return this.fetchCustomsData('invoices')
-  }
-
-  async readCustomsDeclarationsCheckouts() {
-    return this.fetchCustomsData('checkouts')
-  }
-
   build(arrivals, customsInvoices, customsCheckouts, callback) {
     const content = this.buildContent(arrivals, customsInvoices, customsCheckouts)
     const docDefinition = {
@@ -112,27 +43,8 @@ class InvoicesReport {
   }
 
   buildContent(arrivals, customsInvoices, customsCheckouts) {
-    const filteredArrivals = this.filterArrivals(arrivals)
-    const arrivalRecipients = this.groupArrivalsByRecipient(filteredArrivals)
-    const customsRecipients = this.groupCustomsDeclarationsByRecipient(customsInvoices)
-
-    customsRecipients[this.checkoutRecipientName] = customsCheckouts
-
-    let recipientNames = Array.from(new Set([
-      ...Object.keys(arrivalRecipients),
-      ...Object.keys(customsRecipients)
-    ]))
-
-    // sort names; checkoutRecipientName always first, cashRecipientName second (when present)
-    const hasCash = arrivalRecipients[this.cashRecipientName] !== undefined
-    recipientNames = recipientNames.filter(
-      name => name !== this.checkoutRecipientName && name !== this.cashRecipientName
-    )
-    recipientNames.sort()
-    if (hasCash) {
-      recipientNames.unshift(this.cashRecipientName)
-    }
-    recipientNames.unshift(this.checkoutRecipientName)
+    const {arrivalRecipients, customsRecipients, recipientNames} =
+      this.groupAll(arrivals, customsInvoices, customsCheckouts)
 
     const monthLabel = this.getMonthLabel()
 
@@ -158,70 +70,6 @@ class InvoicesReport {
     return content
   }
 
-  filterArrivals(arrivals) {
-    const filtered: any[] = []
-
-    arrivals.forEach(record => {
-      const arrival = firebaseToLocal(record.val());
-      if (arrival.paymentMethod && arrival.paymentMethod.status !== 'pending') {
-        filtered.push(arrival)
-      }
-    });
-
-    return filtered
-  }
-
-  groupArrivalsByRecipient(arrivals) {
-    // Null-prototype: invoiceRecipientName is user-controlled, so a value like
-    // '__proto__' or 'constructor' must be an ordinary key, not touch the
-    // prototype chain (which would corrupt grouping / crash the report).
-    const recipients = Object.create(null)
-
-    arrivals.forEach(arrival => {
-      const invoiceRecipientName = arrival.paymentMethod.method === 'invoice'
-        ? arrival.paymentMethod.invoiceRecipientName
-        : arrival.paymentMethod.method === 'checkout'
-          ? this.checkoutRecipientName
-          : arrival.paymentMethod.method === 'cash'
-            ? this.cashRecipientName
-            : undefined
-
-      if (invoiceRecipientName) {
-        if (!recipients[invoiceRecipientName]) {
-          recipients[invoiceRecipientName] = []
-        }
-
-        recipients[invoiceRecipientName].push(arrival)
-      }
-    });
-
-    return recipients
-  }
-
-  groupCustomsDeclarationsByRecipient(customsDeclarations) {
-    // Null-prototype: invoiceRecipientName is user-controlled, so a value like
-    // '__proto__' or 'constructor' must be an ordinary key, not touch the
-    // prototype chain (which would corrupt grouping / crash the report).
-    const recipients = Object.create(null)
-
-    customsDeclarations.forEach(customsDeclaration => {
-      const invoiceRecipientName = customsDeclaration.invoiceRecipientName
-
-      if (!recipients[invoiceRecipientName]) {
-        recipients[invoiceRecipientName] = []
-      }
-
-      recipients[invoiceRecipientName].push(customsDeclaration)
-    });
-
-    return recipients
-  }
-
-  getMonthLabel() {
-    const monthName = t(`months.${this.month - 1}`)
-    return `${monthName} ${this.year}`
-  }
-
   addLandingFeesTable(recipientName, arrivals, content) {
     if (!arrivals || arrivals.length === 0) {
       return
diff --git a/src/util/InvoicesReportData.spec.ts b/src/util/InvoicesReportData.spec.ts
new file mode 100644
index 00000000..8326a875
--- /dev/null
+++ b/src/util/InvoicesReportData.spec.ts
@@ -0,0 +1,107 @@
+describe('util', () => {
+  describe('InvoicesReportData', () => {
+    let InvoicesReportData;
+    let get;
+
+    beforeEach(() => {
+      global.__CONF__ = {
+        aerodrome: {
+          ICAO: 'LSZT',
+          runways: [{name: '10', type: 'A'}, {name: '28', type: 'A'}],
+        },
+        enabledFlightTypes: {0: 'private', 1: 'instruction'},
+        memberManagement: false,
+      };
+
+      jest.resetModules();
+      jest.mock('./firebase');
+      jest.mock('firebase/database', () => ({
+        get: jest.fn(),
+        query: jest.fn(ref => ref),
+        orderByChild: jest.fn(),
+        startAt: jest.fn(),
+        endAt: jest.fn(),
+      }));
+
+      get = require('firebase/database').get;
+      InvoicesReportData = require('./InvoicesReportData').default;
+    });
+
+    function makeArrivalsSnapshot(arrivals) {
+      const records = arrivals.map(arrival => ({
+        val: () => ({
+          dateTime: new Date(`${arrival.date}T${arrival.time}:00`).toISOString(),
+          immatriculation: 'HB-KOF',
+          paymentMethod: arrival.paymentMethod,
+        }),
+      }));
+      return {forEach: fn => records.forEach(fn)};
+    }
+
+    // collect() is the wiring InvoicesExcelReport.generate() actually calls in
+    // production: readArrivals + the two customs endpoints, fed into groupAll.
+    // Nothing else exercises it end to end.
+    describe('collect', () => {
+      it('fetches arrivals and customs data and groups them by recipient', async () => {
+        get.mockResolvedValue(makeArrivalsSnapshot([
+          {
+            date: '2023-06-01', time: '10:00',
+            paymentMethod: {method: 'invoice', status: 'paid', invoiceRecipientName: 'Company A'},
+          },
+          {
+            date: '2023-06-02', time: '11:00',
+            paymentMethod: {method: 'checkout', status: 'paid'},
+          },
+        ]));
+
+        const report = new InvoicesReportData(2023, 6);
+        report.readCustomsDeclarationsInvoices = jest.fn().mockResolvedValue([
+          {invoiceRecipientName: 'Company A', date: '2023-06-01', fee: 10},
+        ]);
+        report.readCustomsDeclarationsCheckouts = jest.fn().mockResolvedValue([
+          {date: '2023-06-03', fee: 5},
+        ]);
+
+        const {recipientNames, arrivalRecipients, customsRecipients} = await report.collect();
+
+        expect(recipientNames).toEqual(['Online-Zahlungen', 'Company A']);
+        expect(arrivalRecipients['Company A']).toHaveLength(1);
+        expect(customsRecipients['Company A']).toHaveLength(1);
+        // The checkout customs declarations are filed under the same recipient
+        // name as checkout arrivals.
+        expect(customsRecipients['Online-Zahlungen']).toHaveLength(1);
+      });
+
+      it('excludes pending arrivals, matching the PDF report', async () => {
+        get.mockResolvedValue(makeArrivalsSnapshot([
+          {
+            date: '2023-06-01', time: '10:00',
+            paymentMethod: {method: 'invoice', status: 'pending', invoiceRecipientName: 'Company A'},
+          },
+        ]));
+
+        const report = new InvoicesReportData(2023, 6);
+        report.readCustomsDeclarationsInvoices = jest.fn().mockResolvedValue([]);
+        report.readCustomsDeclarationsCheckouts = jest.fn().mockResolvedValue([]);
+
+        const {recipientNames, arrivalRecipients} = await report.collect();
+
+        // The checkout recipient placeholder is always present (it carries the
+        // customs checkouts group even when there are none); the pending
+        // arrival's recipient must not be.
+        expect(recipientNames).toEqual(['Online-Zahlungen']);
+        expect(arrivalRecipients['Company A']).toBeUndefined();
+      });
+
+      it('rejects when a customs endpoint fails', async () => {
+        get.mockResolvedValue(makeArrivalsSnapshot([]));
+
+        const report = new InvoicesReportData(2023, 6);
+        report.readCustomsDeclarationsInvoices = jest.fn().mockRejectedValue(new Error('down'));
+        report.readCustomsDeclarationsCheckouts = jest.fn().mockResolvedValue([]);
+
+        await expect(report.collect()).rejects.toThrow('down');
+      });
+    });
+  });
+});
diff --git a/src/util/InvoicesReportData.ts b/src/util/InvoicesReportData.ts
new file mode 100644
index 00000000..80718ee3
--- /dev/null
+++ b/src/util/InvoicesReportData.ts
@@ -0,0 +1,199 @@
+import firebase, {getIdToken} from './firebase';
+import {get, query, orderByChild, startAt, endAt} from 'firebase/database';
+import {firebaseToLocal} from './movements';
+import dates from '../util/dates';
+import i18n from '../i18n';
+
+const t = i18n.getFixedT('de');
+
+import moment from 'moment';
+
+/**
+ * Everything the invoice recipient reports need before rendering: fetching the
+ * arrivals and customs declarations for a month, and grouping them by invoice
+ * recipient. Rendering is left to the subclasses (PDF / Excel), so both formats
+ * are guaranteed to show the same data in the same order.
+ */
+class InvoicesReportData {
+
+  get checkoutRecipientName() {
+    return t('invoicesReport.onlinePayments');
+  }
+
+  get cashRecipientName() {
+    return t('invoicesReport.cashPayments');
+  }
+
+  year: number;
+  month: number;
+  startDate: string;
+  endDate: string;
+  creationDate: any;
+  options: any;
+
+  constructor(year, month, options = {}) {
+    const monthStr = (month < 10 ? '0' : '') + month
+    const day = '01';
+
+    this.year = year
+    this.month = month
+
+    this.startDate = year + '-' + monthStr + '-' + day;
+    this.endDate = moment(this.startDate).endOf('month').format('YYYY-MM-DD');
+
+    this.creationDate = moment();
+
+    this.options = options;
+  }
+
+  /**
+   * Fetch the month's data and group it by invoice recipient.
+   */
+  collect() {
+    return Promise.all([
+      this.readArrivals(),
+      this.readCustomsDeclarationsInvoices(),
+      this.readCustomsDeclarationsCheckouts()
+    ]).then(([arrivalsResult, customsInvoices, customsCheckouts]) =>
+      this.groupAll(arrivalsResult, customsInvoices, customsCheckouts))
+  }
+
+  /**
+   * Group already fetched data by invoice recipient, in display order.
+   */
+  groupAll(arrivals, customsInvoices, customsCheckouts) {
+    const arrivalRecipients = this.groupArrivalsByRecipient(this.filterArrivals(arrivals))
+    const customsRecipients = this.groupCustomsDeclarationsByRecipient(customsInvoices)
+
+    customsRecipients[this.checkoutRecipientName] = customsCheckouts
+
+    return {
+      arrivalRecipients,
+      customsRecipients,
+      recipientNames: this.getRecipientNames(arrivalRecipients, customsRecipients)
+    }
+  }
+
+  readArrivals() {
+    return get(query(
+      firebase('/arrivals'),
+      orderByChild('dateTime'),
+      startAt(dates.isoStartOfDay(this.startDate)),
+      endAt(dates.isoEndOfDay(this.endDate))
+    ));
+  }
+
+  async fetchCustomsData(endpoint) {
+    const idToken = await getIdToken()
+    const url = `https://europe-west1-${__FIREBASE_PROJECT_ID__}.cloudfunctions.net/api/customs/${endpoint}?year=${this.year}&month=${this.month}`
+    const response = await fetch(url, {
+      headers: {
+        'Authorization': `Bearer ${idToken}`
+      }
+    })
+
+    if (!response.ok) {
+      console.log(`Failed to fetch customs ${endpoint}`, response)
+      throw new Error(`Failed to fetch customs ${endpoint}`)
+    }
+
+    return await response.json()
+  }
+
+  async readCustomsDeclarationsInvoices() {
+    return this.fetchCustomsData('invoices')
+  }
+
+  async readCustomsDeclarationsCheckouts() {
+    return this.fetchCustomsData('checkouts')
+  }
+
+  filterArrivals(arrivals) {
+    const filtered: any[] = []
+
+    arrivals.forEach(record => {
+      const arrival = firebaseToLocal(record.val());
+      if (arrival.paymentMethod && arrival.paymentMethod.status !== 'pending') {
+        filtered.push(arrival)
+      }
+    });
+
+    return filtered
+  }
+
+  groupArrivalsByRecipient(arrivals) {
+    // Null-prototype: invoiceRecipientName is user-controlled, so a value like
+    // '__proto__' or 'constructor' must be an ordinary key, not touch the
+    // prototype chain (which would corrupt grouping / crash the report).
+    const recipients = Object.create(null)
+
+    arrivals.forEach(arrival => {
+      const invoiceRecipientName = arrival.paymentMethod.method === 'invoice'
+        ? arrival.paymentMethod.invoiceRecipientName
+        : arrival.paymentMethod.method === 'checkout'
+          ? this.checkoutRecipientName
+          : arrival.paymentMethod.method === 'cash'
+            ? this.cashRecipientName
+            : undefined
+
+      if (invoiceRecipientName) {
+        if (!recipients[invoiceRecipientName]) {
+          recipients[invoiceRecipientName] = []
+        }
+
+        recipients[invoiceRecipientName].push(arrival)
+      }
+    });
+
+    return recipients
+  }
+
+  groupCustomsDeclarationsByRecipient(customsDeclarations) {
+    // Null-prototype: invoiceRecipientName is user-controlled, so a value like
+    // '__proto__' or 'constructor' must be an ordinary key, not touch the
+    // prototype chain (which would corrupt grouping / crash the report).
+    const recipients = Object.create(null)
+
+    customsDeclarations.forEach(customsDeclaration => {
+      const invoiceRecipientName = customsDeclaration.invoiceRecipientName
+
+      if (!recipients[invoiceRecipientName]) {
+        recipients[invoiceRecipientName] = []
+      }
+
+      recipients[invoiceRecipientName].push(customsDeclaration)
+    });
+
+    return recipients
+  }
+
+  /**
+   * Recipient names in display order: online payments first, cash payments
+   * second (when present), everything else alphabetically.
+   */
+  getRecipientNames(arrivalRecipients, customsRecipients) {
+    let recipientNames = Array.from(new Set([
+      ...Object.keys(arrivalRecipients),
+      ...Object.keys(customsRecipients)
+    ]))
+
+    const hasCash = arrivalRecipients[this.cashRecipientName] !== undefined
+    recipientNames = recipientNames.filter(
+      name => name !== this.checkoutRecipientName && name !== this.cashRecipientName
+    )
+    recipientNames.sort()
+    if (hasCash) {
+      recipientNames.unshift(this.cashRecipientName)
+    }
+    recipientNames.unshift(this.checkoutRecipientName)
+
+    return recipientNames
+  }
+
+  getMonthLabel() {
+    const monthName = t(`months.${this.month - 1}`)
+    return `${monthName} ${this.year}`
+  }
+}
+
+export default InvoicesReportData;
diff --git a/src/util/downloadBlob.spec.ts b/src/util/downloadBlob.spec.ts
new file mode 100644
index 00000000..8ce3a8a7
--- /dev/null
+++ b/src/util/downloadBlob.spec.ts
@@ -0,0 +1,58 @@
+import downloadBlob from './downloadBlob';
+
+describe('util', () => {
+  describe('downloadBlob', () => {
+    let createObjectURL;
+    let revokeObjectURL;
+
+    beforeEach(() => {
+      createObjectURL = jest.fn(() => 'blob:fake-url');
+      revokeObjectURL = jest.fn();
+      (URL as any).createObjectURL = createObjectURL;
+      (URL as any).revokeObjectURL = revokeObjectURL;
+    });
+
+    it('clicks a download link pointing at the blob', () => {
+      const clicks: any[] = [];
+      const originalCreateElement = document.createElement.bind(document);
+      jest.spyOn(document, 'createElement').mockImplementation(tagName => {
+        const element = originalCreateElement(tagName);
+        if (tagName === 'a') {
+          element.click = () => clicks.push({
+            href: element.getAttribute('href'),
+            download: element.getAttribute('download'),
+          });
+        }
+        return element;
+      });
+
+      const blob = new Blob(['x']);
+      downloadBlob('report.xlsx', blob);
+
+      expect(createObjectURL).toHaveBeenCalledWith(blob);
+      expect(clicks).toEqual([{href: 'blob:fake-url', download: 'report.xlsx'}]);
+
+      (document.createElement as any).mockRestore();
+    });
+
+    it('removes the link from the document', () => {
+      downloadBlob('report.xlsx', new Blob(['x']));
+      expect(document.querySelectorAll('a')).toHaveLength(0);
+    });
+
+    it('revokes the object url only after the click has been processed', () => {
+      jest.useFakeTimers();
+      try {
+        downloadBlob('report.xlsx', new Blob(['x']));
+        // Revoking synchronously can cancel a download the browser has only
+        // queued, so it must not have happened yet.
+        expect(revokeObjectURL).not.toHaveBeenCalled();
+
+        jest.runAllTimers();
+        expect(revokeObjectURL).toHaveBeenCalledWith('blob:fake-url');
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+  });
+});
diff --git a/src/util/downloadBlob.ts b/src/util/downloadBlob.ts
new file mode 100644
index 00000000..ba73244d
--- /dev/null
+++ b/src/util/downloadBlob.ts
@@ -0,0 +1,21 @@
+/**
+ * Trigger a browser download for an in-memory blob (used for the generated
+ * Excel workbooks, which are too large to inline as a data URI).
+ */
+const downloadBlob = (filename: string, blob: Blob) => {
+  const url = URL.createObjectURL(blob);
+
+  const link = document.createElement('a');
+  link.setAttribute('href', url);
+  link.setAttribute('download', filename);
+
+  document.body.appendChild(link);
+  link.click();
+  document.body.removeChild(link);
+
+  // Some browsers start the download asynchronously, so revoking in this tick
+  // can cancel it before it begins.
+  setTimeout(() => URL.revokeObjectURL(url), 0);
+};
+
+export default downloadBlob;
diff --git a/src/util/loadExcelJs.spec.ts b/src/util/loadExcelJs.spec.ts
new file mode 100644
index 00000000..564016ee
--- /dev/null
+++ b/src/util/loadExcelJs.spec.ts
@@ -0,0 +1,32 @@
+describe('util', () => {
+  describe('loadExcelJs', () => {
+    describe('resolveWorkbookConstructor', () => {
+      let resolveWorkbookConstructor;
+
+      beforeEach(() => {
+        resolveWorkbookConstructor = require('./loadExcelJs').resolveWorkbookConstructor;
+      });
+
+      it('uses Workbook when it is exposed directly on the namespace', () => {
+        class FakeWorkbook {}
+        const result = resolveWorkbookConstructor({Workbook: FakeWorkbook, default: {}});
+        expect(result).toBe(FakeWorkbook);
+      });
+
+      it('falls back to default.Workbook, as a raw ESM dynamic import exposes it', () => {
+        class FakeWorkbook {}
+        const result = resolveWorkbookConstructor({default: {Workbook: FakeWorkbook}});
+        expect(result).toBe(FakeWorkbook);
+      });
+    });
+
+    describe('default export', () => {
+      it('resolves with the Workbook constructor from a real dynamic import', async () => {
+        const loadWorkbookConstructor = require('./loadExcelJs').default;
+        const Workbook = await loadWorkbookConstructor();
+        expect(typeof Workbook).toBe('function');
+        expect(new Workbook()).toBeInstanceOf(Workbook);
+      });
+    });
+  });
+});
diff --git a/src/util/loadExcelJs.ts b/src/util/loadExcelJs.ts
new file mode 100644
index 00000000..d635a63e
--- /dev/null
+++ b/src/util/loadExcelJs.ts
@@ -0,0 +1,24 @@
+/**
+ * exceljs weighs about a megabyte, so it is loaded on demand. Keeping the
+ * dynamic import in its own module lets webpack split it into a separate chunk
+ * that is only fetched when a report is actually generated, and gives tests a
+ * single seam to stub.
+ */
+
+/**
+ * Under a raw ESM dynamic import, a CJS module like exceljs is only reachable
+ * via `.default`; some bundler/interop combinations instead (or additionally)
+ * expose its named exports directly on the namespace object. Exported as a
+ * pure function so both shapes can be tested deterministically — a mocked
+ * dynamic import goes through Babel's own interop shim, which does not
+ * reliably keep the two shapes distinct.
+ */
+export const resolveWorkbookConstructor = (excelJsModule: any): any =>
+  excelJsModule.Workbook || excelJsModule.default.Workbook;
+
+const loadWorkbookConstructor = async (): Promise<any> => {
+  const excelJs: any = await import('exceljs');
+  return resolveWorkbookConstructor(excelJs);
+};
+
+export default loadWorkbookConstructor;
diff --git a/src/util/report.spec.ts b/src/util/report.spec.ts
new file mode 100644
index 00000000..bcab1255
--- /dev/null
+++ b/src/util/report.spec.ts
@@ -0,0 +1,49 @@
+global.__CONF__ = {
+  aerodrome: {
+    ICAO: 'LSZT',
+    runways: [{name: '10', type: 'A'}, {name: '28', type: 'A'}],
+  },
+  enabledFlightTypes: {0: 'private', 1: 'instruction'},
+  memberManagement: false,
+};
+
+// invoicesExcel is a thin wrapper, but it is the one place that forwards
+// (year, month, options) into the InvoicesExcelReport constructor — nothing
+// else in the suite goes through this file, so an argument-order slip here
+// (e.g. swapping year/month) would otherwise go uncaught.
+jest.mock('./InvoicesExcelReport', () => {
+  const construct = jest.fn();
+  const MockInvoicesExcelReport = jest.fn().mockImplementation(function (this: any, ...args: any[]) {
+    construct(...args);
+    this.generate = jest.fn().mockResolvedValue('the-blob');
+  });
+  (MockInvoicesExcelReport as any).__construct = construct;
+  return {__esModule: true, default: MockInvoicesExcelReport};
+});
+
+describe('util', () => {
+  describe('report', () => {
+    describe('invoicesExcel', () => {
+      it('forwards year, month and options to InvoicesExcelReport and resolves with its result', async () => {
+        const {invoicesExcel} = require('./report');
+        const InvoicesExcelReport = require('./InvoicesExcelReport').default;
+        const options = {format: 'excel'};
+
+        const result = await invoicesExcel(2024, 11, options);
+
+        expect((InvoicesExcelReport as any).__construct).toHaveBeenCalledWith(2024, 11, options);
+        expect(result).toBe('the-blob');
+      });
+
+      it('propagates a rejection instead of swallowing it', async () => {
+        const InvoicesExcelReport = require('./InvoicesExcelReport').default;
+        InvoicesExcelReport.mockImplementationOnce(function (this: any) {
+          this.generate = jest.fn().mockRejectedValue(new Error('failed'));
+        });
+        const {invoicesExcel} = require('./report');
+
+        await expect(invoicesExcel(2024, 11, {})).rejects.toThrow('failed');
+      });
+    });
+  });
+});
diff --git a/src/util/report.ts b/src/util/report.ts
index fa6614c4..ffecd6d6 100644
--- a/src/util/report.ts
+++ b/src/util/report.ts
@@ -2,6 +2,7 @@ import MovementReport from './MovementReport';
 import LandingsReport from './LandingsReport';
 import YearlySummaryReport from './YearlySummaryReport';
 import InvoicesReport from './InvoicesReport'
+import InvoicesExcelReport from './InvoicesExcelReport'
 
 export function airstat(year, month, options) {
   return new Promise(resolve => {
@@ -38,3 +39,9 @@ export function invoices(year, month, options) {
       });
   });
 }
+
+export function invoicesExcel(year, month, options) {
+  // Unlike the callback-based reports above, this one propagates failures so
+  // the caller can stop showing the report as being generated.
+  return new InvoicesExcelReport(year, month, options).generate();
+}
diff --git a/webpack.config.js b/webpack.config.js
index 942873b7..813e3465 100755
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -38,6 +38,9 @@ module.exports = {
   output: {
     path: path.resolve(__dirname, './build'),
     filename: 'bundle.[contenthash].js',
+    // Lazily loaded chunks get their own prefix so the service worker can keep
+    // them out of the precache (see GenerateSW below).
+    chunkFilename: 'chunk.[contenthash].js',
     clean: true,
   },
   resolve: {
@@ -100,7 +103,9 @@ module.exports = {
       new GenerateSW({
         clientsClaim: true,
         skipWaiting: true,
-        exclude: [/\.map$/, /index\.html$/],
+        // Lazily loaded chunks are fetched on demand; precaching them would
+        // make every user download code they may never run.
+        exclude: [/\.map$/, /index\.html$/, /^chunk\./],
         runtimeCaching: [{
           urlPattern: ({request}) => request.mode === 'navigate',
           handler: 'NetworkFirst',

From 7d23f5d50bbb7f1989cfee2b7cc4e9d82eafcd9d Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Mon, 24 Aug 2026 19:19:58 +0000
Subject: [PATCH 2/2] Drop stale "(PDF)" suffix from invoice reports label

The export page section was labelled "Rechnungsberichte herunterladen
(PDF)" / "Download invoice reports (PDF)", which became inaccurate
once the report form gained an Excel option alongside PDF.
---
 src/locales/de.json | 2 +-
 src/locales/en.json | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/locales/de.json b/src/locales/de.json
index 31f47d84..34c8f837 100644
--- a/src/locales/de.json
+++ b/src/locales/de.json
@@ -377,7 +377,7 @@
   "adminExport": {
     "bazlReport": "BAZL-Report herunterladen (CSV)",
     "landingList": "Landeliste herunterladen (CSV)",
-    "invoiceReports": "Rechnungsberichte herunterladen (PDF)",
+    "invoiceReports": "Rechnungsberichte herunterladen",
     "yearlySummary": "Jahreszusammenfassung herunterladen (CSV)"
   },
   "adminAircraft": {
diff --git a/src/locales/en.json b/src/locales/en.json
index 391da19f..33cc8144 100644
--- a/src/locales/en.json
+++ b/src/locales/en.json
@@ -377,7 +377,7 @@
   "adminExport": {
     "bazlReport": "Download FOCA report (CSV)",
     "landingList": "Download landing list (CSV)",
-    "invoiceReports": "Download invoice reports (PDF)",
+    "invoiceReports": "Download invoice reports",
     "yearlySummary": "Download yearly summary (CSV)"
   },
   "adminAircraft": {