Claude Central Gateway

A lightweight proxy that translates Claude API requests to OpenAI's API, enabling cost optimization through cheaper third-party providers. Deploy on Vercel, Cloudflare Workers, or any Hono-compatible platform with zero configuration beyond environment variables.

Key Features:

• ✅ Full tool use/tool result support with proper round-trip handling
• ✅ Streaming responses with Anthropic SSE format
• ✅ Image content (base64 and URLs)
• ✅ System message arrays
• ✅ Timing-safe authentication (x-api-key header)
• ✅ Stop sequences and stop reason mapping
• ✅ Token usage tracking

Where to Find Cheap LLM Providers?

Check out this repo for a list of affordable OpenAI-compatible providers.

Philosophy

Minimal, simple, deploy anywhere. No GUI, no database, no complexity.

Quick Start

Deploy to Vercel

Or manually:

git clone https://github.com/tiennm99/claude-central-gateway
cd claude-central-gateway
npm install
vercel

Deploy to Cloudflare Workers

git clone https://github.com/tiennm99/claude-central-gateway
cd claude-central-gateway
npm install
npm run deploy:cf

Set Environment Variables

Vercel: Dashboard → Settings → Environment Variables

Cloudflare: wrangler.toml or Dashboard → Workers → Variables

Variable	Description	Example
GATEWAY_TOKEN	Shared token for authentication	my-secret-token
OPENAI_API_KEY	Your OpenAI API key	sk-...
MODEL_MAP	Model name mapping	claude-sonnet-4-20250514:gpt-4o

Configure Claude Code

export ANTHROPIC_BASE_URL=https://your-gateway.vercel.app
export ANTHROPIC_AUTH_TOKEN=my-secret-token
claude

Environment Variables

Variable	Required	Description	Example
GATEWAY_TOKEN	Yes	Shared token for authentication via x-api-key header	my-secret-token-123
OPENAI_API_KEY	Yes	OpenAI API key (with usage credits)	sk-proj-...
MODEL_MAP	No	Model name mappings (comma-separated, format: claude-model:openai-model)	claude-sonnet-4-20250514:gpt-4o,claude-opus:gpt-4-turbo

Features & Compatibility

Fully Supported

• Messages: Text, images (base64 & URLs), tool results
• Tools: Tool definitions, tool_use/tool_result round-trips, tool_choice constraints
• System: String or array of text blocks
• Streaming: Full SSE support with proper event sequencing
• Parameters: max_tokens, temperature, top_p, stop_sequences
• Metadata: Token usage counting, stop_reason mapping

Unsupported (Filtered Out)

• Thinking blocks (Claude-specific)
• Cache control directives
• Vision-specific parameters

See API Reference for complete endpoint documentation.

Why This Project?

Why not use a local proxy, like Claude Code Router?

Local proxies only work on a single machine. This project serves multiple machines simultaneously.

Why not use LiteLLM?

LiteLLM requires a dedicated VPS, consumes more resources, and costs more to deploy.

Why no advanced features like routing or GUI management?

Built for personal use. Simplicity over features.

Not Suitable For

• Single-machine localhost proxy → Use Claude Code Router
• Enterprise/Team usage with GUI management → Use LiteLLM
• Advanced routing, load balancing, rate limiting, per-user auth → Use LiteLLM or similar

Documentation

• API Reference - Complete endpoint documentation and examples
• System Architecture - Request flow, data structures, deployment topology
• Code Standards - Module responsibilities, naming conventions, security practices
• Project Overview & PDR - Requirements, roadmap, product strategy

Development

Project Structure

src/
├── index.js                  # Hono app entry point
├── auth-middleware.js        # x-api-key validation with timing-safe comparison
├── openai-client.js          # Cached OpenAI client, model mapping
├── transform-request.js      # Anthropic → OpenAI transformation
├── transform-response.js     # OpenAI → Anthropic SSE streaming
└── routes/
    └── messages.js           # POST /v1/messages handler

Building Locally

npm install
npm run dev              # Start local server (localhost:5173)

Testing

# Manual test with curl
curl -X POST http://localhost:5173/v1/messages \
  -H "x-api-key: test-token" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 256,
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Deployment Checklist

• Set GATEWAY_TOKEN to a strong random value (32+ characters)
• Set OPENAI_API_KEY to your actual OpenAI API key
• Configure MODEL_MAP if using non-standard model names
• Test with Claude Code: export ANTHROPIC_BASE_URL=... and export ANTHROPIC_AUTH_TOKEN=...
• Monitor OpenAI API usage and costs
• Rotate GATEWAY_TOKEN periodically
• Consider rate limiting if exposed to untrusted networks