Open-source Spike alternatives

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.

UnInbox is an open-source communication platform that reimagines email for teams and professionals. Its README argues that email has changed little since the late 1970s while volume and noise have grown, so it builds a modern layer on top of email rather than trying to replace it. The project lists Hey, Front and Missive as products it is an alternative to.

Features described as native include team collaboration, conversation notes and a new-sender screener. It is built to work with your current email infrastructure or to replace it entirely, and the maintainers say email is only the start of a broader communication infrastructure. A hosted app is live at app.uninbox.com, and the team asks users to join its Discord for updates and feedback.

The stack is TypeScript with Next.js and React for the web app, Hono for the public API, Tailwind CSS and tRPC for type-safe APIs. The repository metadata lists the license as Other, so check the license file for the exact terms. It is positioned as open communication infrastructure that teams can build on.