Use Firebase Authentication (Phone SMS OTP, Google, Email) with Better Auth sessions, organizations, and plugins. No Twilio needed for phone auth.
Latest release v2.2.2 · 15 Sept 2026
2 files for Codex, OpenCode and Claude Code: better-auth-firebase-auth AGENTS.md, better-auth-firebase-auth CLAUDE.md — 2,443 tokens loaded in every session.
AGENTS.md A 2,438 tok CLAUDE.md A 5 tok These files are yultyyev/better-auth-firebase-auth's own configuration — they tell Codex, OpenCode and Claude Code how to work on this repository, so they are not mods to install elsewhere. Copy one as a starting point and replace the parts that are about this project.