Quidly

Self-Assessment, sorted. — free, self-hosted UK-landlord bookkeeping and tax.

Quidly is a self-hosted bookkeeping and tax app for UK landlords: track rent and expenses across your properties, then turn them into an SA105 you can file with your Self Assessment tax return. It handles the £1,000 property allowance, the Section 24 finance-cost reducer, Scottish tax bands, and limited-company landlords too. Run it on your own box, keep your own data.

Screenshots

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Quick start

mkdir quidly && cd quidly
curl -O https://raw.githubusercontent.com/WarlaxZ/quidly/main/docker-compose.yml
curl -o .env https://raw.githubusercontent.com/WarlaxZ/quidly/main/.env.example
# set SESSION_SECRET in .env, then generate a login:
docker compose run --rm quidly npm run set-password   # paste the Docker-Compose hash into .env
docker compose up -d                                   # open http://localhost:3000

That pulls the prebuilt multi-arch image (linux/amd64 and linux/arm64, so a Raspberry Pi or ARM VPS works). See Self-hosting for the $ gotcha, HTTPS, and building from source instead.

Who it's for

Landlords who file their own Self Assessment and would rather not keep the books in a spreadsheet — whether that's one buy-to-let, an HMO, or a portfolio across several properties, held personally or through a limited company.

If you're currently on Akaunting, there's a migration path that brings your transactions, vendors and categories across.

What it is

Quidly is free and self-hosted, with a UK-first design. Money is stored as integer pence end-to-end — there is no floating-point arithmetic in the money path, so nothing drifts or rounds unexpectedly. Each install is single-user. Quidly is not affiliated with HMRC; it produces estimates, not tax advice.

How it compares

	Quidly	Spreadsheet	Landlord SaaS	General accounting software
Cost	Free	Free	Monthly subscription	Monthly subscription
Your data stays on your hardware	✅	✅	❌	❌
Knows what an SA105 box is	✅	❌	Varies	❌
Section 24 finance-cost reducer	✅	Manual	Varies	❌
Scottish tax bands	✅	Manual	Varies	Varies
Limited-company landlord support	✅	Manual	Varies	✅
Won't silently mis-round your figures	✅	❌	—	—
Multi-user / multi-tenant	❌	—	✅	✅
Files directly with HMRC	❌	❌	Varies	Varies

Deliberate trade-offs, not oversights: Quidly is single-user per install, UK-only, and produces figures and a PDF rather than submitting to HMRC for you.

Features

• Bookkeeping — transactions, recurring rules, one-click bank-CSV import, multi-property.
• Mortgages & loans — model a loan once and Quidly splits every payment into deductible interest (SA105 box 44) and non-deductible capital repayment, shows your effective rate after the Section 24 reducer, and reconciles the year against your lender's statement.
• Receipt scanning — optional AI extraction using your own Anthropic key.
• SA105 & personal tax — £1,000 property allowance, Section 24 finance-cost reducer, Scottish bands, and SA105 PDF export.
• Limited companies — corporation tax (including marginal relief), dividends, director's loan s455 + benefit-in-kind.
• Deductions assistant — mileage log and use-of-home claims.
• Plan ahead — a what-if planner plus a salary-vs-dividend optimiser.
• Light & dark themes.

Self-hosting with Docker

The Quick start above pulls ghcr.io/warlaxz/quidly. To build from this checkout instead:

git clone https://github.com/WarlaxZ/quidly.git && cd quidly
cp .env.example .env                                    # then set SESSION_SECRET
docker compose -f docker-compose.yml -f docker-compose.build.yml run --rm quidly npm run set-password
docker compose -f docker-compose.yml -f docker-compose.build.yml up -d --build

Password hash & the $ gotcha. Docker Compose interpolates bare $ in env_file values as variable references and strips them. Put the argon2 hash in .env with each $ doubled ($$). set-password prints exactly that "Docker-Compose" form for you — it prints three forms in total: the dev backslash-escaped form, the Docker-Compose doubled form, and the raw unescaped hash. Use the Docker-Compose one here.

Data persists in the quidly-data Docker volume — the SQLite database and uploads both live under /data, so they survive restarts and upgrades. Back that volume up.

Upgrading. docker compose pull && docker compose up -d. Migrations run automatically on start.

COOKIE_SECURE. Leave it unset (the secure default) when serving behind HTTPS. Set COOKIE_SECURE=false only if you serve plain HTTP on a trusted LAN, otherwise login cookies won't be sent.

Verifying the image. Published images carry signed build provenance:

gh attestation verify oci://ghcr.io/warlaxz/quidly:latest -R WarlaxZ/quidly

HTTPS reverse proxy (Caddy)

quidly.example.com {
    reverse_proxy localhost:3000
}

Caddy auto-provisions and renews TLS certificates for you. Behind HTTPS, leave COOKIE_SECURE unset. Traefik and nginx work equally well — just point the proxy at localhost:3000.

Local development

npm install
npm run set-password            # paste the DEV (backslash-escaped) hash into .env
# .env also needs SESSION_SECRET=... (openssl rand -base64 32) and DATABASE_URL="file:./dev.db"
npx prisma migrate deploy       # apply migrations (Prisma v7: hand-authored SQL)
npx prisma db seed              # seed HMRC categories
npm run dev                     # http://localhost:3000

npm test                        # vitest
npm run typecheck               # tsc --noEmit
npm run build                   # next build

Prisma v7 note: the datasource URL is configured in prisma.config.ts (read from DATABASE_URL), and migrations are hand-authored SQL applied with migrate deploy — not migrate dev.

See CONTRIBUTING.md for conventions — in particular the integer-pence rule and the requirement that tax-rate changes cite an HMRC source.

Migrating from Akaunting

Import your existing Akaunting data (transactions, vendors, categories) into Quidly.

Prerequisites: Docker (for the analyse step) and a MySQL/MariaDB dump of your Akaunting database (.sql).

# 1. Analyse the dump — loads it into a throwaway MariaDB and writes a review pack
npm run migrate:akaunting:analyse -- ./akaunting-migration/dump.sql

# 2. Review akaunting-migration/report.md (incl. "what's missing") and edit
#    akaunting-migration/mapping.json — set a "target" for any unmapped category.

# 3. Dry-run (writes nothing), then apply for real
npm run migrate:akaunting:apply -- --dry-run
npm run migrate:akaunting:apply

# Optional: also copy receipt files from Akaunting's storage folder
npm run migrate:akaunting:apply -- --attachments-dir /path/to/akaunting/storage

Each Akaunting company becomes a Quidly property, categories are mapped onto SA105 boxes (you review the suggestions), and recurring items carry across. Amounts are treated as GBP; non-GBP transactions are listed and skipped. The import is idempotent — re-running is safe and never duplicates (imported rows are tagged with an externalRef). Files under akaunting-migration/ are git-ignored as they may contain financial data.

📖 Full walkthrough: docs/migrating-from-akaunting.md — how to export your Akaunting dump, review the category mapping, handle recurring items and attachments, and troubleshoot.

Configuration

.env.example is the annotated source of truth; the table below summarises it.

Variable	Required	Description
AUTH_USERNAME	Yes	Login username. Generated together with the hash by npm run set-password.
AUTH_PASSWORD_HASH	Yes	argon2id password hash. Use the form matching your setup (dev / Docker-Compose / raw).
SESSION_SECRET	Yes	Long random secret (32+ chars), e.g. openssl rand -base64 32.
DATABASE_URL	Set by Docker	SQLite connection string. Dev default file:./dev.db; Docker sets file:/data/quidly.db.
UPLOAD_DIR	Set by Docker	Upload directory. Dev default ./uploads; Docker sets /data/uploads.
COOKIE_SECURE	Optional	Set to false only for plain-HTTP on a trusted LAN. Leave unset behind HTTPS.
ANTHROPIC_API_KEY	Optional	Enables AI receipt scanning, using your own Anthropic key. Receipt images are sent to Anthropic; leave unset to keep everything local.
EXTRACTION_MODEL	Optional	Vision model for receipt extraction. Defaults to a cheap vision-capable Claude model.

Tech stack

Next.js 16 (App Router) · Prisma v7 + SQLite (better-sqlite3 adapter) · Tailwind v4 · iron-session + argon2id · Vitest · Docker.

Tax accuracy & caveats

Quidly produces estimates, not advice — verify HMRC rates each April against the official guidance. Rates are configured for the 2025-26, 2026-27 and 2027-28 tax years; years outside that range fall back to the latest configured year with an in-app notice.

Finance-cost relief changes in 2027-28. The Section 24 reducer rises from 20% to 22% for England, Wales and Northern Ireland from 6 April 2027, alongside the matching +2pp property-income rate surcharge. Scotland stays at 20% pending Holyrood adopting an equivalent surcharge, so its 2027-28 figures are flagged provisional in-app.

Quidly does not submit anything to HMRC. It produces the figures and an SA105 PDF; you or your accountant do the filing. Making Tax Digital for Income Tax is being phased in for landlords — check HMRC's guidance for whether it applies to you yet, because Quidly cannot make quarterly digital submissions on your behalf.

Each install is single-tenant. Found a figure that looks wrong? Please open a tax-accuracy issue with an HMRC link — those are the most useful reports this project gets.

Contributing & security

• CONTRIBUTING.md — conventions, scope, and what makes a good PR.
• SECURITY.md — please report vulnerabilities privately, not as public issues.

Licence

Licensed under AGPL-3.0. Quidly is open, but the AGPL means that if you run a modified version as a network service, you must share your changes with its users. Commercial or hosted licensing from the author is possible if the AGPL doesn't fit your use.