Uploaded .docx and .xlsx files are corrupted when using tus-server-node with Supabase S3 Storage

[enriquesantos-dev]

Bug report

• I confirm this is a bug with Supabase, not with my own application.
• I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com).

Describe the bug

When uploading .docx and .xlsx files using tus-server-node with @tus/s3-store (configured to use Supabase Storage via S3-compatible API), the files are saved corrupted. They cannot be opened by Microsoft Word, Excel, or Google Docs/Sheets after being uploaded.

Interestingly, .pdf files upload and open correctly using the exact same pipeline. Additionally, when I tested the same codebase with a native AWS S3 bucket instead of Supabase, all file types — including .docx and .xlsx — worked correctly. This suggests the issue may be related to Supabase's S3 compatibility.

To Reproduce

https://github.com/EnriqueSantos-dev/uppy-tus-server-supabase-s3-bug

Expected behavior

The uploaded .docx and .xlsx files should be saved and retrievable in a usable format, just like .pdf files. All supported MIME types should be stored without corruption.

Screenshots

No visual errors, but files are unreadable after upload. Opening them triggers a warning or error from Google Docs/Excel indicating the file is invalid or corrupted.

System information

OS: windows (wsl 2)

Browser: Chrome (latest)

Version of supabase-js: N/A (upload uses direct S3-compatible API)

Version of Node.js: 22.15.0

Server: Next.js v15.1.8 (App Router)

tus-server-node: @tus/server v2.2.0 and @tus/s3-store v2.0.0

Client: uppy.js v4.4.4 with @uppy/tus v4.2.2

Additional context

Here is a summary of my configuration:

• @tus/s3-store is configured with forcePathStyle: true and uses Supabase credentials.

• uppy.js is configured with the correct MIME types:

  allowedFileTypes: [
    "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
  ]

• Files are uploaded successfully, but corrupted when retrieved — even directly from the Supabase dashboard.

• Uploading to a native AWS S3 bucket using the exact same setup works perfectly for all file types.