Open WebUI

Open WebUI can use ModRouter through the plain OpenAI-compatible /v1 API.

Endpoint

https://api.modrouter.online/v1

Set MODROUTER_BASE_URL from the Open WebUI runtime environment to the ModRouter root URL reachable by Open WebUI.

Open Open WebUI admin settings.
Add an OpenAI-compatible connection.
Set URL to your ModRouter /v1 endpoint.
Set API Key to a ModRouter virtual key, or a placeholder value if auth is disabled.
Let Open WebUI fetch models from /v1/models, or add model IDs manually.

Example model IDs:

openai/gpt-4o-mini
anthropic/claude-sonnet-4-5
gemini/gemini-2.5-pro
groq/llama-3.3-70b-versatile

Open WebUI deployments can also set the OpenAI-compatible base URL through environment variables:

OPENAI_API_BASE_URLS="https://api.modrouter.online/v1"
OPENAI_API_KEYS="${MODROUTER_API_KEY}"

Use /v1, not /openai, for the normal Open WebUI connection.
If you use SSO and want ModRouter to attribute users, ensure Open WebUI forwards the bearer token or a virtual key header accepted by your ModRouter deployment.