ou're correct, this error is happening because your LangFuse instance isn't configured to connect to an S3-compatible blob storage service. LangFuse requires this external storage to save trace data and other large objects, and it must be set up separately from the main application.

The error Failed to upload events to blob storage means the S3 connection details are either missing or incorrect in your Railway environment variables.

## How to Fix It: Configure Blob Storage

The easiest way to solve this is to use a dedicated object storage service and provide the credentials to LangFuse. Services like Cloudflare R2 or Backblaze B2 are great choices as they are S3-compatible and offer generous free tiers.

Step 1: Create an S3-Compatible Bucket

1. Sign up for a service like Cloudflare R2.

2. Create a new "Bucket". Note down the bucket name.

3. Generate API credentials. You will receive an Endpoint URL, Access Key ID, and a Secret Access Key.

Step 2: Set Environment Variables in Railway

Go to your LangFuse service in the Railway dashboard, navigate to the Variables tab, and add the following environment variables using the credentials from Step 1:

• BUCKET_NAME: The name of the bucket you created.

• S3_ENDPOINT: The full endpoint URL provided by your storage service (e.g., https://<account_id>.r2.cloudflarestorage.com).

• AWS_ACCESS_KEY_ID: The access key ID you generated.

• AWS_SECRET_ACCESS_KEY: The secret access key you generated.

• S3_REGION: The region of your bucket (e.g., auto for Cloudflare R2).

Step 3: Redeploy

After adding these variables, redeploy your LangFuse service. It will now be able to connect to your bucket and store the trace data correctly, resolving the 500 error.

## Alternative for Testing: Local File Storage

If you're just testing and don't want to set up an external service, you can configure LangFuse to use the local filesystem.

1. Attach a Volume: In your LangFuse service settings on Railway, go to the Volumes tab and add a new volume (e.g., mount path /data).

2. Set Environment Variable: Add the following environment variable to your service: LANGFUSE_STORAGE=local.

Note: This local storage method is not recommended for production. It's less durable and scalable than a dedicated object storage service like R2 or S3.