OneMux/Docs/Protocol Support

Protocol Support

OneMux supports four protocol formats: OpenAI, Anthropic, Gemini, and Responses API. Developers can choose the optimal protocol for each model's capabilities and switch without modifying existing code. This page lists the endpoints, authentication methods, and use cases for each protocol.

Supported Protocols

Protocol	Endpoint	Supported Models	Authentication
OpenAI-compatible	/v1/chat/completions	All models	Authorization: Bearer sk-xxx
Native Anthropic	/v1/messages	Claude models	x-api-key: sk-xxx
OpenAI Responses	/v1/responses	GPT models	Authorization: Bearer sk-xxx
Native Gemini	/v1beta/models/{model}:generateContent	Gemini models	Authorization: Bearer sk-xxx

Why Are There Multiple Protocols?

Easy migration: Keep your existing code and change only the Base URL
Full native feature support: Supports features such as Anthropic Prompt Caching, Claude Extended Thinking, and Gemini 2M context
Optimal performance: Claude is 20-30% faster with the Anthropic protocol than with the OpenAI format

Recommended Usage

Model	Recommended Protocol	Reason
Claude models	Native Anthropic	Supports Prompt Caching, reducing costs by 90%
GPT models	OpenAI-compatible	Standard format with the broadest compatibility
Gemini models	Native Gemini	Supports 2M context for processing very long documents

OpenAI-Compatible Format

curl https://api.onemux.net/v1/chat/completions \
  -H "Authorization: Bearer sk-xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5-5",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Native Anthropic Format (Recommended for Claude)

curl https://api.onemux.net/v1/messages \
  -H "x-api-key: sk-xxx" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5-5",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Native Gemini Format

curl https://api.onemux.net/v1beta/models/gemini-4-argon:generateContent \
  -H "Authorization: Bearer sk-xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{
      "role": "user",
      "parts": [{"text": "Hello"}]
    }]
  }'