Yes, it's totally possible, although the Railway AI might not be powerful enough for this task, so you might need to guide it a bit. Maybe if you provide this to the AI it might be able to pull it off:

Basically, you will need to create an S3Client using Bun's built-in client:

const client = new S3Client({
  accessKeyId: process.env.AWS_ACCESS_KEY_ID ?? "",
  secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY ?? "",
  bucket: process.env.AWS_BUCKET_NAME ?? "",
  endpoint: process.env.AWS_ENDPOINT_URL ?? "",
});

For the environment variables, you can go to your bucket and click the Add to Service button.

Make sure that all upload/download functionality is implemented server-side. No environment variables should be exposed to the client. If the use case allows it, use pre-signed URLs for uploading and downloading instead of proxying the data.

Here's a simple example of how the routes would look:

const server = Bun.serve({
  routes: {
    "/health": new Response("OK"),
    
    "/api/presigned-url": async () => {
      // Generate a pre-signed URL for client-side uploads
      const uploadUrl = client.presign("uploads/image.jpg", {
        method: "PUT",
        expiresIn: 3600,
        type: "image/jpeg",
        acl: "public-read"
      });
      return Response.json({ url: uploadUrl });
    },
    
    // Fallback for unmatched routes
    "*": () => new Response("Not Found", { status: 404 }),
  }
});

console.log(`Server running at ${server.url}`);

though, I really would recommend using Opus or Codex if you have access to it.

thank you. indeed i have access to claude but didn't think I could get the function + bucket to work. Let me give this a whirl as I ended up getting claude to write this as a full blown react app lmao. meanwhile a simple bun would be way easier to maintain.

indeed i took your response and threw it in the AI and now it worked. thank you!

Great, do you have any remaining issue/problem?