Antigravity API Proxy

Turn your Google Antigravity account into a fully functional API. Use Claude and Gemini models with any application that supports OpenAI or Anthropic APIs.

Your App  ───▶  Antigravity API Proxy  ───▶  Google Antigravity (Cloud Code)
                 (localhost:8080)

What it does:

• Connects to Google Antigravity using your Google account
• Exposes OpenAI and Anthropic compatible API endpoints
• Generates API keys you can use in any app (Cursor, Continue, LangChain, etc.)
• Manages multiple accounts for higher throughput
• Logs all requests with full prompts and responses

Installation

Option 1: npm (Recommended)

npx @jabezpauls/antigravity-api-proxy@latest start

Option 2: Clone Repository

git clone https://github.com/jabezpauls/antigravity-api-proxy.git
cd antigravity-api-proxy
npm install
npm start

Server runs on http://localhost:8080.

Quick Start

1. Start the Proxy

npx @jabezpauls/antigravity-api-proxy start

2. Add Your Google Account

Open http://localhost:8080 in your browser, go to Accounts, and click Add Account. Complete the Google OAuth flow.

Or via CLI:

npx @jabezpauls/antigravity-api-proxy accounts add

3. Create an API Key

Go to API Keys → Create Key. Copy the generated key (starts with sk-ag-).

4. Use the API

curl http://localhost:8080/v1/chat/completions \
  -H "Authorization: Bearer sk-ag-your-key-here" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-4", "messages": [{"role": "user", "content": "Hello!"}]}'

Usage Examples

OpenAI SDK (Python)

from openai import OpenAI

client = OpenAI(
    base_url="http://localhost:8080/v1",
    api_key="sk-ag-your-key-here"
)

response = client.chat.completions.create(
    model="gpt-4",
    messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)

Anthropic SDK (Python)

import anthropic

client = anthropic.Anthropic(
    base_url="http://localhost:8080",
    api_key="sk-ag-your-key-here"
)

response = client.messages.create(
    model="gemini-3-flash",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}]
)
print(response.content[0].text)

Claude Code CLI

Edit ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "http://localhost:8080",
    "ANTHROPIC_AUTH_TOKEN": "sk-ag-your-key-here",
    "ANTHROPIC_MODEL": "gemini-3-flash"
  }
}

Cursor / Continue / Other Apps

Set these in your app's settings:

• API Base URL: http://localhost:8080/v1
• API Key: sk-ag-your-key-here
• Model: gpt-4 or any model from the list below

Available Models

Gemini Models

| Model | Description | |-------|-------------| | gemini-3-flash | Fast, good for most tasks | | gemini-3-pro-low | Pro quality, lower quota usage | | gemini-3-pro-high | Pro quality, higher limits | | gemini-2.5-flash | Gemini 2.5 Flash | | gemini-2.5-flash-lite | Cheapest option | | gemini-2.5-pro | Gemini 2.5 Pro |

Claude Models

| Model | Description | |-------|-------------| | claude-sonnet-4-5 | Claude Sonnet 4.5 | | claude-sonnet-4-5-thinking | With extended thinking | | claude-opus-4-5-thinking | Claude Opus with thinking |

OpenAI Model Names (Auto-mapped)

| Use This | Gets You | |----------|----------| | gpt-4 | claude-opus-4-5-thinking | | gpt-4o | gemini-3-pro-high | | gpt-3.5-turbo | gemini-3-flash |

API Key Features

Create keys with restrictions:

• Model Restrictions: Allow only specific models (gemini-*, claude-*)
• Rate Limits: Set requests per minute/hour
• IP Whitelisting: Restrict to specific IPs
• Expiration: Auto-expire keys on a date
• Request Logging: Full prompt/response history per key

Create via Web UI or API:

curl -X POST http://localhost:8080/api/keys \
  -H "Content-Type: application/json" \
  -d '{
    "name": "My App Key",
    "allowed_models": ["gemini-*"],
    "rate_limit_rpm": 60
  }'

Multi-Account Support

Add multiple Google accounts to increase your API throughput. The proxy automatically switches accounts when one hits rate limits.

# Add more accounts
npx @jabezpauls/antigravity-api-proxy accounts add

# Choose load balancing strategy
npx @jabezpauls/antigravity-api-proxy start --strategy=round-robin  # Rotate each request
npx @jabezpauls/antigravity-api-proxy start --strategy=sticky       # Stay on one account
npx @jabezpauls/antigravity-api-proxy start --strategy=hybrid       # Smart selection (default)

Web Dashboard

Access at http://localhost:8080:

| Tab | What It Does | |-----|--------------| | Dashboard | Real-time stats, quota usage | | Accounts | Add/remove Google accounts | | API Keys | Create and manage API keys | | Request Logs | View all requests with full content | | Settings | Server configuration |

API Endpoints

| Endpoint | Method | Description | |----------|--------|-------------| | /v1/chat/completions | POST | OpenAI-compatible chat | | /v1/messages | POST | Anthropic-compatible messages | | /v1/models | GET | List available models | | /api/keys | GET/POST | Manage API keys | | /api/logs/requests | GET | View request logs | | /health | GET | Health check | | /account-limits | GET | Account quotas |

Full API documentation: See API.md for detailed endpoint reference, request/response formats, code examples, and best practices.

CLI Reference

# Start server
npx @jabezpauls/antigravity-api-proxy start
npx @jabezpauls/antigravity-api-proxy start --strategy=sticky
npx @jabezpauls/antigravity-api-proxy start --debug

# Manage accounts
npx @jabezpauls/antigravity-api-proxy accounts           # Interactive menu
npx @jabezpauls/antigravity-api-proxy accounts add       # Add account
npx @jabezpauls/antigravity-api-proxy accounts add --no-browser  # Headless mode
npx @jabezpauls/antigravity-api-proxy accounts list      # List accounts
npx @jabezpauls/antigravity-api-proxy accounts verify    # Check token validity

Environment Variables

| Variable | Description | |----------|-------------| | PORT | Server port (default: 8080) | | WEBUI_PASSWORD | Password protect the dashboard | | DEBUG | Enable debug logging |

Troubleshooting

Can't connect:

• Make sure the proxy is running: npx @jabezpauls/antigravity-api-proxy start
• Check health: curl http://localhost:8080/health

401 Unauthorized:

• Your Google token may have expired
• Re-add your account or refresh: curl -X POST http://localhost:8080/refresh-token

429 Rate Limited:

• Add more Google accounts for higher limits
• Check quotas: curl "http://localhost:8080/account-limits?format=table"

Model not allowed:

• Check your API key's allowed models in the Web UI

Risk Notice

• Not affiliated with Google or Anthropic
• May violate Terms of Service - use at your own risk
• For personal/development use only
• Your account could be suspended

License

MIT

Credits

Forked from badrisnarayanan/antigravity-claude-proxy.

Based on opencode-antigravity-auth and claude-code-proxy.