API overview

Base URL

Family	Base URL
OpenAI-compatible	https://apimaster.ai/v1
Anthropic-compatible	https://apimaster.ai (no /v1)
Gemini (if enabled)	https://apimaster.ai (see console)

Authentication

Authorization: Bearer <API_KEY>

Anthropic-style routes may accept x-api-key: <API_KEY> as well.

Main endpoints

Method	Path	Description
POST	/chat/completions	OpenAI Chat Completions
GET	/models	Models available to your account
POST	/messages	Anthropic Messages (when enabled)
POST	/images/generations	Image generation (GPT-Image-2, etc.) — overview
GET	/tasks/{task_id}	Poll async image tasks

Use https://apimaster.ai/v1 for OpenAI SDK / Codex; use https://apimaster.ai as the Anthropic base URL (no /v1) for Claude Code and the Messages API.

Errors

JSON error bodies follow OpenAI/Anthropic conventions. Use HTTP status and error.message for retries.

Rate limits

Start with modest concurrency. On 429, use exponential backoff.

See Chat Completions and Models.