---

name: Implementing Better Auth description: Claude implements enterprise TypeScript authentication with Better Auth. Use when building auth systems, adding OAuth providers, enabling MFA, or managing sessions in TypeScript/Next.js projects.

Implementing Better Auth

Quick Start

Copy// lib/auth.ts
import { betterAuth } from "better-auth";
import { prismaAdapter } from "better-auth/adapters/prisma";

export const auth = betterAuth({
  database: prismaAdapter(prisma, { provider: "postgresql" }),
  emailAndPassword: { enabled: true, requireEmailVerification: true },
  session: { expiresIn: 60 * 60 * 24 * 7 },
  socialProviders: {
    google: { clientId: process.env.GOOGLE_CLIENT_ID!, clientSecret: process.env.GOOGLE_CLIENT_SECRET! },
  },
});

Features

Common Patterns

Client Setup with Plugins

Copy// lib/auth-client.ts
import { createAuthClient } from "better-auth/client";
import { twoFactorClient, organizationClient } from "better-auth/client/plugins";

export const authClient = createAuthClient({
  baseURL: process.env.NEXT_PUBLIC_API_URL,
  plugins: [twoFactorClient(), organizationClient()],
});

export const { signIn, signUp, signOut, useSession } = authClient;

Protected Routes Middleware

Copy// middleware.ts
import { auth } from "@/lib/auth";
import { NextRequest, NextResponse } from "next/server";

export async function middleware(request: NextRequest) {
  const session = await auth.api.getSession({ headers: request.headers });

  if (!session && !request.nextUrl.pathname.startsWith("/login")) {
    return NextResponse.redirect(new URL("/login", request.url));
  }
  return NextResponse.next();
}

Two-Factor Authentication Flow

Copy// Handle 2FA during sign-in
const { data, error } = await authClient.signIn.email({ email, password });

if (error?.code === "TWO_FACTOR_REQUIRED") {
  // Show 2FA input
  const { data: verified } = await authClient.twoFactor.verify({ code: totpCode });
}

// Enable 2FA for user
const { data } = await authClient.twoFactor.enable();
// data.totpURI contains QR code data
// data.backupCodes contains recovery codes

Best Practices

References

• Better Auth Documentation
• Better Auth Plugins
• OWASP Authentication Guidelines