Stack Auth

Stack Auth is the open-source Auth0 alternative. We focus on reducing overhead in starting and growing new projects, maintaining startup agility while ensuring reliability. We innovate with AI/RPA and snapshots for frontend and E2E tests, and offer superior API migration tooling. We work closely with databases and infrastructure, addressing scale challenges and building integrations for customers. Well-funded and backed by YC, Paul Graham, Guillermo Rauch, Khosla Ventures, and more.