Antigravity Claude Proxy: Free Model Access

Purpose and Significance

Antigravity Claude Proxy is a bridge that unlocks access to Claude and Gemini models through an Anthropic-compatible API, enabling developers to use these models with Claude Code CLI and OpenClaw without requiring direct Anthropic subscriptions. By translating requests between Anthropic's Messages API format and Google's Generative AI infrastructure, it democratizes access to advanced AI models while maintaining API compatibility with existing Claude-based workflows.

Key Features

• Anthropic API Compatibility: Drop-in replacement for Claude API—works seamlessly with Claude Code CLI, OpenClaw, and ClawdBot without code changes
• Multi-Model Support: Access both Claude (via Antigravity Cloud Code) and Google Gemini models through a unified proxy interface
• Flexible Authentication: Three authorization methods—web dashboard with OAuth, CLI-based account management, or automatic detection of existing Antigravity sessions
• Full Streaming & Thinking Support: Maintains extended thinking capabilities and response streaming when proxying requests
• Web Dashboard: Built-in UI for account management, quota monitoring, model configuration, and Claude CLI settings synchronization
• Headless Mode: Supports remote server deployments with manual authorization for environments without browser access
• Account Quota Visibility: Check rate limits and usage via health check endpoints or table-formatted CLI output
• Custom Port Configuration: Run on any port via environment variables for containerized and multi-proxy setups

How It Works

The proxy intercepts requests in Anthropic Messages API format, retrieves OAuth tokens from configured Google accounts (or detects local Antigravity sessions), transforms payloads to Google Generative AI format, and forwards them to Antigravity's Cloud Code API. Responses are converted back to Anthropic format with full streaming and thinking support intact.

Getting Started

Installation

Quickest path (recommended): Run directly with npx—no installation needed.

npx antigravity-claude-proxy@latest start

Global installation:

npm install -g antigravity-claude-proxy@latest
antigravity-claude-proxy start

From source:

git clone https://github.com/badrisnarayanan/antigravity-claude-proxy.git
cd antigravity-claude-proxy
npm install
npm start

Quick Setup (3 Steps)

1. Start the server: Runs on http://localhost:8080 by default. Use PORT=3001 antigravity-claude-proxy start for custom ports.
2. Authorize a Google account: Open the web dashboard at http://localhost:8080, navigate to Accounts, and click "Add Account" to complete OAuth flow. For headless servers, use the CLI: antigravity-claude-proxy accounts add --no-browser.
3. Configure Claude Code: Use the web console (Settings → Claude CLI) to set base URL, model selection, and sync settings. Or manually edit ~/.claude/settings.json and add environment variables like ANTHROPIC_BASE_URL=http://localhost:8080 and ANTHROPIC_AUTH_TOKEN=test.

Verification

curl http://localhost:8080/health
curl "http://localhost:8080/account-limits?format=table"

Who It's For

• Claude Code Users: Developers using Claude Code CLI who want free or low-cost access to Claude models without Anthropic subscriptions
• OpenClaw & ClawdBot Users: Teams leveraging these AI tools who need cost-effective model routing
• Antigravity Users: Existing Antigravity app users seeking deeper integration with Claude-based tooling
• Developers Exploring AI APIs: Engineers learning about proxy patterns, API translation, and multi-model orchestration
• Self-Hosted AI Teams: Organizations running containerized or on-premise AI infrastructure that need API-compatible model access

Requirements

• Node.js 18 or later
• Google account (for multi-account mode) or existing Antigravity installation (automatic detection)
• Familiarity with environment variables and shell configuration (.zshrc, .bashrc, or PowerShell profiles)

Configuration & Advanced Usage

The proxy supports both web-based and manual configuration. Web Console mode (recommended) provides a GUI for toggling between Proxy Mode (Antigravity Cloud Code) and Paid Mode (official Anthropic). Manual setup requires editing settings.json and exporting environment variables—system variables take precedence over config files, so coordinate carefully if using both methods.

For Gemini models specifically, adjust the env configuration block in settings to point to Google's API format. Headless deployments benefit from the manual authorization flow, where users copy an OAuth URL, complete auth on a local machine, and paste the code back into the remote console.

Community & Support

The project maintains active issue tracking (9 open issues at last update) and welcomes contributions. Check the CLAUDE.md documentation for Claude Code-specific guidance. With 2,610 stars and 355 forks, it has a growing user base—review GitHub Discussions for troubleshooting and use cases.

License & Attribution

Released under the MIT License. Active development as of February 2026. Source: badrisnarayanan/antigravity-claude-proxy on GitHub