Authentication

Calling the gateway endpoints in this documentation requires an API key. The recommended authentication method is the Authorization header.

Bearer Token

Item	Value
Header	Authorization
Format	Bearer YOUR_API_KEY
Applies to	All public gateway endpoints

curl https://api.llmapi.site/v1/usage \
  -H 'Authorization: Bearer YOUR_API_KEY'

Compatible Headers

The server also accepts these headers for client compatibility:

Header	Example
Authorization	Bearer YOUR_API_KEY
x-api-key	YOUR_API_KEY
x-goog-api-key	YOUR_API_KEY

Use only one authentication method per request. New integrations should use Authorization: Bearer.

API Key Types

Create an API key on the website's API Key page and bind it to the group for the platform you want to call.

Type	Binding	Supported endpoints
Regular API key	General group	Text APIs, model listing, usage queries, and synchronous platform image endpoints.

See Create API Keys for the full steps.

Authentication Failure

Interface details:

Item	Value
HTTP status	401
Error type	authentication_error
Trigger	Missing, invalid, or unrecognized API key

Response example:

{
  "type": "error",
  "error": {
    "type": "authentication_error",
    "message": "Invalid API key"
  }
}

Group and Platform Restrictions

Successful authentication does not make every endpoint available.

Key type	Example endpoints	Restrictions
Regular API key / OpenAI group	/v1/responses, /v1/chat/completions, /v1/images/generations, /v1/images/edits	OpenAI-specific endpoints require an OpenAI group.
Regular API key / Anthropic group	/v1/messages, /v1/messages/count_tokens	OpenAI-specific image endpoints are unavailable.
Regular API key / Gemini group	/v1beta/models, /v1beta/models/{model}:generateContent	OpenAI-specific image endpoints are unavailable.

When the platform or key type does not match, the endpoint may return 400, 403, or 404. See Errors for common causes and resolutions.