ChatJS is an open-source, production-ready foundation for building AI-powered chat applications without recreating common infrastructure from scratch.

It provides a complete starter codebase that includes authentication, message handling, streaming, file uploads, and multi-model support, allowing developers to focus on building unique product features instead of boilerplate systems.

The platform integrates access to over 120 AI models—including providers like GPT, Claude, Gemini, and others—through a unified interface. It supports modern application features such as resumable streaming, branching conversations, attachments, web search, image generation, and sandboxed code execution.

Built with a modern TypeScript stack (Next.js, PostgreSQL, Redis, and AI SDK tooling), ChatJS is designed to be easily customizable and extensible. Developers can fork the project, adapt it to their needs, and deploy quickly, making it especially useful for startups and teams building AI chat products or internal tools.

Key features include:

• Access to 120+ AI models through a unified API
• Built-in authentication (GitHub, Google, anonymous)
• Streaming chat with resumable sessions
• File attachments (images, PDFs, documents)
• Web search, image generation, and code execution tools
• Branching conversations and sharing links
• Modern full-stack TypeScript architecture

Common use cases include:

• Building AI chat applications
• Creating internal AI tools
• Prototyping conversational interfaces
• Launching SaaS products with chat features
• Integrating multi-model AI capabilities into web apps