n8n

n8n's [OI] node accepts a custom base URL in its credential. That keeps workflows readable and gives you model selection in the node.

Create the credential

1. 1

   Add an [OI] node

   Search for [OI] in the node panel and add it to the workflow.
2. 2

   Create a credential

   Choose Create new credential.
3. 3

   Set the base URL

   Enter https://api.relayrouter.org/v1 as the base URL and paste your key as the API key.
4. 4

   Pick a model

   Save, then choose or type a model id from the catalog.

HTTP Request alternative

Method: POST
URL:    https://api.relayrouter.org/v1/chat/completions
Header: Authorization: Bearer {{$credentials.relayApiKey}}
Header: Content-Type: application/json
Body:   {
  "model": "deepseek-v4.1-flash",
  "messages": [{ "role": "user", "content": "{{$json.prompt}}" }]
}