claude-code-proxy

Connect Claude Code to alternative models from OpenAI or Gemini.

Forked from: 1rgs/claude-code-proxy

• Quick start
• Installation
  • Prerequisites
  • Configuration
  • Using with Claude Code 🎮
• Model Mapping 🗺️
  • Supported Models
    • OpenAI Models
    • Gemini Models
  • Model Prefix Handling
  • Customizing Model Mapping
• How It Works 🧩
• Contributing 🤝

Quick start

uvx claude-code-proxy

Installation

Prerequisites

• Set OPENAI_API_KEY or GEMINI_API_KEY in your environment.
• Install uv:
  • Install docs here: https://docs.astral.sh/uv/getting-started/installation
  • On MacOS: brew install uv
  • On Windows: winget install astral-sh.uv

Configuration

[!WARNING]
Readme rewrite is in progress on everything below

3. Configure Environment Variables: Copy the example environment file:

   cp .env.example .env
   

   Edit .env and fill in your API keys and model configurations:

   • ANTHROPIC_API_KEY: (Optional) Needed only if proxying to Anthropic models.
   • OPENAI_API_KEY: Your OpenAI API key (Required if using the default OpenAI preference or as fallback).
   • GEMINI_API_KEY: Your Google AI Studio (Gemini) API key (Required if PREFERRED_PROVIDER=google).
   • PREFERRED_PROVIDER (Optional): Set to openai (default) or google. This determines the primary backend for mapping haiku/sonnet.
   • BIG_MODEL (Optional): The model to map sonnet requests to. Defaults to gpt-4.1 (if PREFERRED_PROVIDER=openai) or gemini-2.5-pro-preview-03-25.
   • SMALL_MODEL (Optional): The model to map haiku requests to. Defaults to gpt-4.1-mini (if PREFERRED_PROVIDER=openai) or gemini-2.0-flash.

   Mapping Logic:

   • If PREFERRED_PROVIDER=openai (default), haiku/sonnet map to SMALL_MODEL/BIG_MODEL prefixed with openai/.
   • If PREFERRED_PROVIDER=google, haiku/sonnet map to SMALL_MODEL/BIG_MODEL prefixed with gemini/ if those models are in the server's known GEMINI_MODELS list (otherwise falls back to OpenAI mapping).

4. Run the server:

   uv run uvicorn server:app --host 0.0.0.0 --port 8082 --reload
   

   (--reload is optional, for development)

Using with Claude Code 🎮

1. Install Claude Code (if you haven't already):

   npm install -g @anthropic-ai/claude-code
   

2. Connect to your proxy:

   ANTHROPIC_BASE_URL=http://localhost:8082 claude
   

3. That's it! Your Claude Code client will now use the configured backend models (defaulting to Gemini) through the proxy. 🎯

Model Mapping 🗺️

The proxy automatically maps Claude models to either OpenAI or Gemini models based on the configured model:

Claude Model	Default Mapping	When BIG_MODEL/SMALL_MODEL is a Gemini model
haiku	openai/gpt-4o-mini	gemini/[model-name]
sonnet	openai/gpt-4o	gemini/[model-name]

Supported Models

OpenAI Models

The following OpenAI models are supported with automatic openai/ prefix handling:

• o3-mini
• o1
• o1-mini
• o1-pro
• gpt-4.5-preview
• gpt-4o
• gpt-4o-audio-preview
• chatgpt-4o-latest
• gpt-4o-mini
• gpt-4o-mini-audio-preview
• gpt-4.1
• gpt-4.1-mini

Gemini Models

The following Gemini models are supported with automatic gemini/ prefix handling:

• gemini-2.5-pro-preview-03-25
• gemini-2.0-flash

Model Prefix Handling

The proxy automatically adds the appropriate prefix to model names:

• OpenAI models get the openai/ prefix
• Gemini models get the gemini/ prefix
• The BIG_MODEL and SMALL_MODEL will get the appropriate prefix based on whether they're in the OpenAI or Gemini model lists

For example:

• gpt-4o becomes openai/gpt-4o
• gemini-2.5-pro-preview-03-25 becomes gemini/gemini-2.5-pro-preview-03-25
• When BIG_MODEL is set to a Gemini model, Claude Sonnet will map to gemini/[model-name]

Customizing Model Mapping

Control the mapping using environment variables in your .env file or directly:

Example 1: Default (Use OpenAI) No changes needed in .env beyond API keys, or ensure:

OPENAI_API_KEY="your-openai-key"
GEMINI_API_KEY="your-google-key" # Needed if PREFERRED_PROVIDER=google
# PREFERRED_PROVIDER="openai" # Optional, it's the default
# BIG_MODEL="gpt-4.1" # Optional, it's the default
# SMALL_MODEL="gpt-4.1-mini" # Optional, it's the default

Example 2: Prefer Google

GEMINI_API_KEY="your-google-key"
OPENAI_API_KEY="your-openai-key" # Needed for fallback
PREFERRED_PROVIDER="google"
# BIG_MODEL="gemini-2.5-pro-preview-03-25" # Optional, it's the default for Google pref
# SMALL_MODEL="gemini-2.0-flash" # Optional, it's the default for Google pref

Example 3: Use Specific OpenAI Models

OPENAI_API_KEY="your-openai-key"
GEMINI_API_KEY="your-google-key"
PREFERRED_PROVIDER="openai"
BIG_MODEL="gpt-4o" # Example specific model
SMALL_MODEL="gpt-4o-mini" # Example specific model

How It Works 🧩

This proxy works by:

1. Receiving requests in Anthropic's API format 📥
2. Translating the requests to OpenAI format via LiteLLM 🔄
3. Sending the translated request to OpenAI 📤
4. Converting the response back to Anthropic format 🔄
5. Returning the formatted response to the client ✅

The proxy handles both streaming and non-streaming responses, maintaining compatibility with all Claude clients. 🌊

Contributing 🤝

Contributions are welcome! Please feel free to submit a Pull Request. 🎁