Mail0

Zero is an open-source email application presented as a Gmail alternative that applies AI to the inbox. Its authors argue that most email services are closed source, data-hungry or too complex to host yourself, and they position Zero as transparent and privacy-first. It can be self-hosted while also connecting to external services such as Gmail and other email providers.

Listed strengths include a unified inbox that combines multiple providers such as Gmail and Outlook, AI agents and language models that help with email tasks, a customizable interface and an extensible design for developers. The project states that it does not track, collect or sell your data, while noting that data passed to connected external services falls under those services' own privacy terms.

The stack is Next.js, React, TypeScript, Tailwind CSS and shadcn UI on the front end, Node.js with Drizzle ORM on the back end, PostgreSQL for the database, and Better Auth with Google OAuth for sign-in. Running it locally requires recent Node.js, pnpm and Docker, plus environment variable configuration. The code is MIT licensed and the latest release listed is v0.1.