diff --git a/client/packages/admin/src/index.ts b/client/packages/admin/src/index.ts
index 63e8c5c7b2..d4ab71133e 100644
--- a/client/packages/admin/src/index.ts
+++ b/client/packages/admin/src/index.ts
@@ -845,6 +845,10 @@ const isNodeReadable = (v: any): v is Readable =>
 const isWebReadable = (v: any): v is ReadableStream =>
   v && typeof v.getReader === 'function';
 
+function isHeaderSafe(value: string): boolean {
+  return /^[\x20-\x7e\xa0-\xff]*$/.test(value);
+}
+
 /**
  * Functions to manage file storage.
  */
@@ -872,10 +876,14 @@ class Storage {
   ): Promise<UploadFileResponse> => {
     const headers = {
       ...authorizedHeaders(this.config, this.impersonationOpts),
-      path,
     };
+    if (isHeaderSafe(path)) {
+      headers['path'] = path;
+    }
     if (metadata.contentDisposition) {
-      headers['content-disposition'] = metadata.contentDisposition;
+      if (isHeaderSafe(metadata.contentDisposition)) {
+        headers['content-disposition'] = metadata.contentDisposition;
+      }
     }
 
     // headers.content-type will become "undefined" (string)
@@ -906,10 +914,12 @@ class Storage {
       ...(duplex && { duplex }),
     };
 
-    return jsonFetch(
-      `${this.config.apiURI}/admin/storage/upload?app_id=${this.config.appId}`,
-      options,
-    );
+    let url = `${this.config.apiURI}/admin/storage/upload?app_id=${encodeURIComponent(this.config.appId)}&path=${encodeURIComponent(path)}`;
+    if (metadata.contentDisposition) {
+      url += `&content-disposition=${encodeURIComponent(metadata.contentDisposition)}`;
+    }
+
+    return jsonFetch(url, options);
   };
 
   /**
diff --git a/client/packages/components/src/components/explorer/inner-explorer.tsx b/client/packages/components/src/components/explorer/inner-explorer.tsx
index 7eba2ed498..6d5dabf33f 100644
--- a/client/packages/components/src/components/explorer/inner-explorer.tsx
+++ b/client/packages/components/src/components/explorer/inner-explorer.tsx
@@ -1490,6 +1490,10 @@ export async function jsonFetch(
     : Promise.reject({ status: res.status, body: json });
 }
 
+function isHeaderSafe(value: string): boolean {
+  return /^[\x20-\x7e\xa0-\xff]*$/.test(value);
+}
+
 async function upload(
   token: string,
   appId: string,
@@ -1497,15 +1501,20 @@ async function upload(
   customFilename: string,
   apiUri: string,
 ): Promise<boolean> {
-  const headers = {
+  const path = customFilename || file.name;
+  const headers: Record<string, string> = {
     'app-id': appId,
     app_id: appId,
-    path: customFilename || file.name,
     authorization: `Bearer ${token}`,
     'content-type': file.type,
   };
+  if (isHeaderSafe(path)) {
+    headers['path'] = path;
+  }
+
+  const url = `${apiUri}/dash/apps/${appId}/storage/upload?path=${encodeURIComponent(path)}`;
 
-  const data = await jsonFetch(`${apiUri}/dash/apps/${appId}/storage/upload`, {
+  const data = await jsonFetch(url, {
     method: 'PUT',
     headers,
     body: file,
diff --git a/client/packages/core/src/StorageAPI.ts b/client/packages/core/src/StorageAPI.ts
index f5197db748..da9628ba0c 100644
--- a/client/packages/core/src/StorageAPI.ts
+++ b/client/packages/core/src/StorageAPI.ts
@@ -1,5 +1,9 @@
 import { jsonFetch } from './utils/fetch.js';
 
+function isHeaderSafe(value: string): boolean {
+  return /^[\x20-\x7e\xa0-\xff]*$/.test(value);
+}
+
 export type UploadFileResponse = {
   data: {
     id: string;
@@ -32,15 +36,22 @@ export async function uploadFile({
   const headers = {
     'app-id': appId,
     app_id: appId,
-    path,
     authorization: `Bearer ${refreshToken}`,
     'content-type': contentType || file.type,
   };
-  if (contentDisposition) {
+  if (isHeaderSafe(path)) {
+    headers['path'] = path;
+  }
+  if (contentDisposition && isHeaderSafe(contentDisposition)) {
     headers['content-disposition'] = contentDisposition;
   }
 
-  const data = await jsonFetch(`${apiURI}/storage/upload`, {
+  let url = `${apiURI}/storage/upload?app_id=${encodeURIComponent(appId)}&path=${encodeURIComponent(path)}`;
+  if (contentDisposition) {
+    url += `&content-disposition=${encodeURIComponent(contentDisposition)}`;
+  }
+
+  const data = await jsonFetch(url, {
     method: 'PUT',
     headers,
     body: file,
diff --git a/client/www/app/docs/http-api/page.md b/client/www/app/docs/http-api/page.md
index 653d68bbab..a613ba903a 100644
--- a/client/www/app/docs/http-api/page.md
+++ b/client/www/app/docs/http-api/page.md
@@ -323,10 +323,8 @@ You can also manage your app's [storage](/docs/storage) with the HTTP API.
 Upload a file with `PUT /admin/storage/upload`:
 
 ```shell
-curl -X PUT "https://api.instantdb.com/admin/storage/upload" \
+curl -X PUT "https://api.instantdb.com/admin/storage/upload?app_id=$APP_ID&path=snippets/demo.txt" \
   -H "Authorization: Bearer $ADMIN_TOKEN" \
-  -H "App-Id: $APP_ID" \
-  -H "Path: snippets/demo.txt" \
   -H "Content-Type: text/plain" \
   --data-binary "@demo.txt"
 ```
diff --git a/server/src/instant/admin/routes.clj b/server/src/instant/admin/routes.clj
index 9ebf1da15f..b8eb7004ee 100644
--- a/server/src/instant/admin/routes.clj
+++ b/server/src/instant/admin/routes.clj
@@ -627,11 +627,12 @@
 
 (defn upload-put [req]
   (let [{:keys [app-id] :as perms} (get-perms! req :storage/write)
-        params (:headers req)
-        path (ex/get-param! params ["path"] string-util/coerce-non-blank-str)
+        params (merge (w/keywordize-keys (:headers req))
+                      (:params req))
+        path (ex/get-param! params [:path] string-util/coerce-non-blank-str)
         file (ex/get-param! req [:body] identity)
-        content-type (storage-coordinator/coerce-content-type (get params "content-type"))
-        content-disposition (ex/get-optional-param! params ["content-disposition"] string-util/coerce-non-blank-str)
+        content-type (storage-coordinator/coerce-content-type (:content-type params))
+        content-disposition (ex/get-optional-param! params [:content-disposition] string-util/coerce-non-blank-str)
         data (storage-coordinator/upload-file! {:app-id app-id
                                                 :path path
                                                 :content-type content-type
diff --git a/server/src/instant/dash/routes.clj b/server/src/instant/dash/routes.clj
index a8cf75c7e0..1a3d357f9d 100644
--- a/server/src/instant/dash/routes.clj
+++ b/server/src/instant/dash/routes.clj
@@ -1764,8 +1764,9 @@
   (let [{{app-id :id} :app} (req->app-accepting-superadmin-or-ref-token! :collaborator
                                                                          :apps/read
                                                                          req)
-        params (:headers req)
-        path (ex/get-param! params ["path"] string-util/coerce-non-blank-str)
+        params (merge (w/keywordize-keys (:headers req))
+                      (:params req))
+        path (ex/get-param! params [:path] string-util/coerce-non-blank-str)
         file (ex/get-param! req [:body] identity)
         content-type (storage-coordinator/coerce-content-type (:content-type req))
         data (storage-coordinator/upload-file!
diff --git a/server/src/instant/storage/routes.clj b/server/src/instant/storage/routes.clj
index d6bb684129..84d13e2ae4 100644
--- a/server/src/instant/storage/routes.clj
+++ b/server/src/instant/storage/routes.clj
@@ -27,7 +27,8 @@
      :content-disposition (ex/get-optional-param! params [:content-disposition] string-util/coerce-non-blank-str)}))
 
 (defn upload-put [req]
-  (let [params (w/keywordize-keys (:headers req))
+  (let [params (merge (w/keywordize-keys (:headers req))
+                      (:params req))
         ctx (req->app-file! req params)
         file (ex/get-param! req [:body] identity)
         data (storage-coordinator/upload-file! ctx file)]
diff --git a/server/test/instant/admin/routes_test.clj b/server/test/instant/admin/routes_test.clj
index ec9676d4a0..ad0fa927fd 100644
--- a/server/test/instant/admin/routes_test.clj
+++ b/server/test/instant/admin/routes_test.clj
@@ -1088,6 +1088,17 @@
               (is (= 200 (:status ret)))
               (is (some? (-> ret :body :data :id)))))
 
+          (testing "admin can upload a file with a non-ASCII filename via query params"
+            (let [ret (upload-put
+                       {:body (make-file-content)
+                        :params {:path "café à noite.txt"}
+                        :headers {"app-id" app-id
+                                  "authorization" (str "Bearer " admin-token)
+                                  "content-type" "text/plain"}
+                        :content-length 5})]
+              (is (= 200 (:status ret)))
+              (is (some? (-> ret :body :data :id)))))
+
           (testing "user with email can upload"
             (let [ret (upload-put
                        {:body (make-file-content)
diff --git a/server/test/instant/storage/routes_test.clj b/server/test/instant/storage/routes_test.clj
new file mode 100644
index 0000000000..07aa7a8cda
--- /dev/null
+++ b/server/test/instant/storage/routes_test.clj
@@ -0,0 +1,44 @@
+(ns instant.storage.routes-test
+  (:require [clojure.test :as test :refer [deftest is testing]]
+            [instant.storage.routes :as storage-routes]
+            [instant.storage.coordinator :as storage-coordinator]))
+
+(deftest upload-put-reads-path-from-query-params
+  (let [captured-ctx (atom nil)
+        app-id (random-uuid)]
+    (with-redefs [storage-coordinator/upload-file!
+                  (fn [ctx _file]
+                    (reset! captured-ctx ctx)
+                    {:id "fake-file-id"})]
+      (testing "path comes from query params when present"
+        (let [ret (storage-routes/upload-put
+                   {:body "file-contents"
+                    :params {:app_id (str app-id)
+                             :path "café à noite.txt"}
+                    :headers {"app-id" (str app-id)
+                              "content-type" "text/plain"}
+                    :content-length 5})]
+          (is (= 200 (:status ret)))
+          (is (= "café à noite.txt" (:path @captured-ctx)))))
+
+      (testing "path still works from the legacy header for ASCII filenames"
+        (let [ret (storage-routes/upload-put
+                   {:body "file-contents"
+                    :params {}
+                    :headers {"app-id" (str app-id)
+                              "path" "legacy-file.txt"
+                              "content-type" "text/plain"}
+                    :content-length 5})]
+          (is (= 200 (:status ret)))
+          (is (= "legacy-file.txt" (:path @captured-ctx)))))
+
+      (testing "query param takes priority over the header when both are present"
+        (let [ret (storage-routes/upload-put
+                   {:body "file-contents"
+                    :params {:path "café.txt"}
+                    :headers {"app-id" (str app-id)
+                              "path" "stale-ascii-name.txt"
+                              "content-type" "text/plain"}
+                    :content-length 5})]
+          (is (= 200 (:status ret)))
+          (is (= "café.txt" (:path @captured-ctx))))))))