Authentication

LMRouter supports two types of authentication:

• API Key Authentication
• Bring Your Own Key (BYOK)

API Key Authentication

You can create an API key in your dashboard. To use the API key, you can supply it as the Authorization header in your requests:

Authorization: Bearer <LMROUTER_API_KEY>

or as the X-API-Key header:

X-API-Key: <LMROUTER_API_KEY>

OpenAI-compatible clients will supply the API key in the Authorization header by default, and Anthropic-compatible clients will supply the API key in the X-API-Key header by default.

BYOK Authentication

If you want to use your own API key for a third-party provider, you can do so by supplying the API key as the Authorization header in your requests:

Authorization: Bearer BYOK:<THIRD_PARTY_API_KEY>

or as the X-API-Key header:

X-API-Key: BYOK:<THIRD_PARTY_API_KEY>

If you are using your own API key, you can use a custom model supplied by the third-party provider in your requests, even if the model is not supported by LMRouter. Just pass <PROVIDER_NAME>:<MODEL_NAME> as the model name in your requests.

We do not charge you for using your own API key.