GautamVhavle/CatGPT-Gateway

What it solves

CatGPT Gateway allows users to use their existing ChatGPT Plus or Claude accounts as an API without paying for separate official API credits. It bypasses the need for API keys by automating the web interface of these services, making them accessible to any software that supports the OpenAI API protocol.

How it works

The project runs a real Chromium browser in the background (automated via Patchright) that stays logged into the user's account. When a request is sent to the gateway's FastAPI server, it simulates human-like interactions—typing messages and extracting responses from the web page—and converts the output into a standard OpenAI-compatible JSON format. It includes anti-detection measures like stealth patches and viewport jitter to avoid being flagged as a bot.

Who it’s for

Developers who want to integrate Claude or ChatGPT into their own applications, LangChain workflows, or custom scripts using their existing browser-based subscriptions rather than paying for per-token API usage.

Highlights

• OpenAI Compatibility: Works out-of-the-box with the OpenAI Python SDK and LangChain.
• Multi-Provider Support: Supports both Claude (claude.ai) and ChatGPT (chatgpt.com).
• Advanced Features: Supports SSE streaming, multi-turn conversations, vision (image input), and file attachments.
• Tool Calling: Implements function calling via prompt engineering to allow the model to interact with external tools.
• ** qualitative Monitoring**: Includes a live multi-tab visual dashboard (/preview) to monitor the automated browser sessions in real-time.