Translation Proxy

The translation proxy is the core of Claudex. It sits between Claude Code and your AI providers, transparently converting between the Anthropic Messages API and the OpenAI Chat Completions API.

How It Works

Claude Code → Anthropic Messages API request
    │
    └── Claudex Proxy (127.0.0.1:13456)
        │
        ├── DirectAnthropic provider → forward with headers
        │
        ├── OpenAICompatible provider
        │   ├── Translate request: Anthropic → OpenAI Chat Completions
        │   ├── Forward to provider
        │   └── Translate response: OpenAI → Anthropic
        │
        └── OpenAIResponses provider
            ├── Translate request: Anthropic → OpenAI Responses API
            ├── Forward to provider
            └── Translate response: Responses → Anthropic

What Gets Translated

Request Translation (Anthropic → OpenAI)

Anthropic	OpenAI
`system` field	System message in `messages` array
`messages[].content` blocks (text, image, tool_use)	`messages[].content` + `tool_calls`
`tools` array (JSON Schema)	`tools` array (function format)
`tool_choice`	`tool_choice`
`max_tokens`	`max_tokens`
`temperature`, `top_p`	Direct mapping

Response Translation (OpenAI → Anthropic)

OpenAI	Anthropic
`choices[0].message.content`	`content` blocks
`choices[0].message.tool_calls`	`tool_use` content blocks
`finish_reason: stop`	`stop_reason: end_turn`
`finish_reason: tool_calls`	`stop_reason: tool_use`
`usage.prompt_tokens` / `completion_tokens`	`usage.input_tokens` / `output_tokens`

Streaming Translation

Claudex fully supports SSE (Server-Sent Events) streaming, translating OpenAI stream chunks into Anthropic stream events in real time:

OpenAI SSE	Anthropic SSE
First chunk	`message_start` + `content_block_start`
`choices[0].delta.content`	`content_block_delta` (text_delta)
`choices[0].delta.tool_calls`	`content_block_delta` (input_json_delta)
`finish_reason` present	`content_block_stop` + `message_delta` + `message_stop`

The streaming translator maintains a state machine to properly handle tool call accumulation and content block boundaries.

Supported Providers

Provider	Type	Base URL
Anthropic	DirectAnthropic	`https://api.anthropic.com`
MiniMax	DirectAnthropic	`https://api.minimax.io/anthropic`
OpenRouter	OpenAICompatible	`https://openrouter.ai/api/v1`
Grok (xAI)	OpenAICompatible	`https://api.x.ai/v1`
OpenAI	OpenAICompatible	`https://api.openai.com/v1`
DeepSeek	OpenAICompatible	`https://api.deepseek.com`
Kimi/Moonshot	OpenAICompatible	`https://api.moonshot.cn/v1`
GLM (Zhipu)	OpenAICompatible	`https://open.bigmodel.cn/api/paas/v4`
Ollama	OpenAICompatible	`http://localhost:11434/v1`
vLLM	OpenAICompatible	`http://localhost:8000/v1`
ChatGPT/Codex sub	OpenAIResponses	`https://chatgpt.com/backend-api/codex`

Proxy Management

# Start proxy as a daemon
claudex proxy start -d

# Check proxy status
claudex proxy status

# Stop proxy daemon
claudex proxy stop

# Start on a custom port
claudex proxy start -p 8080

When you run claudex run <profile>, the proxy is automatically started in the background if not already running.