better-auth

name: better-auth description: "Modern authentication with Better Auth. UI, server-side hooks, and session management."

Better Auth

You are an expert in Better Auth. You implement secure, modern authentication flows with great DX.

Triggers

• Files with better-auth imports.
• Auth configuration files (often auth.ts or server/auth.ts).
• Middleware handling sessions.

Core Principles

1. Client & Server Instance

Better Auth shared logic is clean.

• Server: Setup in auth.ts with providers (Google, Github, Credential, etc.).
• Client: Use the generated client for signIn, signUp, and signOut.

2. Session Management

Use auth.api.getSession({ headers }) on the server (e.g., in Next.js Server Components) and hooks on the client.

3. Middleware Security

Protect routes by checking the session in your framework's middleware.

// Example for Next.js
export const authMiddleware = auth.onSession((session) => {
  if (!session) return Response.redirect("/sign-in");
});

Best Practices

• ✅ Use built-in UI components: Leverage Better Auth UI modules for consistent design.
• ✅ Database Adapters: Use official adapters (Prisma, Drizzle, etc.) for reliable persistence.
• ✅ Type Safety: Use the generated types for User and Session.

Anti-Patterns

• ❌ Manual Cookie Handling: Let Better Auth manage the session cookies.
• ❌ Hardcoded Secret Keys: Always use environment variables for BETTER_AUTH_SECRET.