Langfuse

Langfuse is an open-source LLM engineering platform for tracing, evaluating, and debugging LLM applications.

Step 1: Create a Langfuse API key

In Langfuse, go to your project’s Settings > API Keys and create a new key pair. Copy both the Secret Key and Public Key.

Step 2: Enable Broadcast in OpenRouter

Go to Settings > Broadcast and toggle Enable Broadcast.

Step 3: Configure Langfuse

Click the edit icon next to Langfuse and enter:

• Secret Key: Your Langfuse Secret Key
• Public Key: Your Langfuse Public Key
• Base URL (optional): Default is https://us.cloud.langfuse.com. Change for other regions or self-hosted instances

Step 4: Test and save

Click Test Connection to verify the setup. The configuration only saves if the test passes.

Step 5: Send a test trace

Make an API request through OpenRouter and view the trace in Langfuse.