Better Auth

Better Auth (better-auth.com) is a modern TypeScript-first authentication framework designed as an alternative to NextAuth / Auth.js and Clerk-style hosted services. It gives you the pieces a real product needs — email/password, magic links, social sign-in, passkeys, MFA, sessions, organizations, roles, admin dashboards, and a rich plugin API — while remaining fully open source (MIT), self-hostable, and framework-agnostic (Next.js, SvelteKit, Nuxt, Remix, Astro, Express, Hono, Bun). The 2026 releases added a first-class MCP plugin that turns any Better Auth-powered app into an OAuth 2.1 authorization server with dynamic client registration, so third-party AI agents (Claude, Cursor, ChatGPT MCP client) can authenticate against your product and receive scoped access tokens. Combined with Better Auth's existing organization, RBAC, and session primitives, this makes it one of the most practical open-source stacks for shipping an authenticated MCP server. Better Auth's community grew explosively through 2026 — thousands of GitHub stars, many production adopters, and a plugin ecosystem that covers passwordless, Stripe billing, 2FA, and organizations. Because it's self-hosted with your own database (Postgres, MySQL, SQLite), you keep control of user data and avoid per-MAU pricing.