diff --git a/src/lib/client/sync-file-system/sfs-file.ts b/src/lib/client/sync-file-system/sfs-file.ts
index 0bc3f16..1699728 100644
--- a/src/lib/client/sync-file-system/sfs-file.ts
+++ b/src/lib/client/sync-file-system/sfs-file.ts
@@ -63,11 +63,14 @@ export class SfsFile {
     if (!this._cache) return;
     const file = await this._cache.getFile();
     const res = await fetch(this._route, {
-      body: file.stream(),
+      body: file,
       method: 'POST',
-      headers: { [SESSION_PROJECT_HEADER]: this._handler.project.id },
+      headers: {
+        [SESSION_PROJECT_HEADER]: this._handler.project.id,
+        'Content-Type': 'application/octet-stream',
+      },
     });
-    if (!res.ok) throw new Error('Failed to sync file');
+    if (!res.ok) throw new Error(`Failed to sync file: ${await res.text()}`);
   }
 
   async getFile(): Promise<FileSystemFile> {
diff --git a/src/routes/fs/project/+server.ts b/src/routes/fs/project/+server.ts
index 0856a26..5238e51 100644
--- a/src/routes/fs/project/+server.ts
+++ b/src/routes/fs/project/+server.ts
@@ -1,3 +1,5 @@
+import { Writable } from 'stream';
+
 import { Exception } from '@utils/exception';
 
 import { useRequestHandler } from '@utils-server/request-handler';
@@ -18,3 +20,23 @@ export const GET = useRequestHandler(({ event, project }) => {
 
   return new Response(stream);
 });
+
+/**
+ * To post a project file, use the following URL:
+ * /fs/project?path=path/to/file
+ * The path must be relative to /client
+ * Only the client is handled for now
+ */
+export const POST = useRequestHandler(async ({ event, project }) => {
+  const path = event.url.searchParams.get('path');
+  if (!path) throw new Exception('Bad Request', 'Missing path query param', 400);
+
+  const file = project.client.fs.getFile(decodeURIComponent(path).replace(/\?url$/, ''));
+
+  if (!event.request.body) throw new Exception('Bad Request', 'Missing body', 400);
+
+  const stream = file.getWriteStream();
+  await event.request.body.pipeTo(Writable.toWeb(stream));
+
+  return Response.json({ success: true });
+});