better-auth

Create a D1 database with wrangler, define a Drizzle schema, then pass drizzleAdapter(drizzle(env.DB), { provider: "sqlite" }) to betterAuth. In v1.5.0+ you can also pass the D1 binding directly. Generate migrations with drizzle-kit and apply them via wrangler d1 migrations apply.

There is no d1Adapter export in Better Auth; that import path does not exist. Use drizzleAdapter from better-auth/adapters/drizzle, Kysely with @noxharmonium/kysely-d1, or pass the D1 binding directly in v1.5.0+.

Better Auth is self-hosted and open source with built-in 2FA, organizations, and passkeys, while Clerk is a paid hosted service and Auth.js offers fewer built-in features. The framework-comparison reference covers feature matrices, migration paths, and cost analysis.

Yes, Better Auth supports 18 frameworks including Next.js, Nuxt, Remix, SvelteKit, Astro, Express, NestJS, Fastify, and Expo. The skill includes framework-specific references for App Router middleware, Nuxt composables, Remix loaders, and mobile SecureStore patterns.

CORS errors occur when credentials: true is missing from your CORS middleware, blocking session cookies. OAuth mismatches happen when the callback URL differs even slightly, such as a trailing slash; it must exactly match https://yourdomain.com/api/auth/callback/google.

v1.5.0 moved the API key plugin to @better-auth/api-key, renamed userId to referenceId, and made after-hooks run post-transaction. v1.6.0 changed session freshAge to use createdAt and enabled SAML InResponseTo validation by default. Dedicated migration guides cover each upgrade.