implementing-better-auth

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

// 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

Feature	Description	Reference
Email/Password Auth	Secure registration, login, password validation	Auth Guide
Social OAuth	Google, GitHub, Discord provider integration	Social Providers
Two-Factor Auth	TOTP-based MFA with backup codes	2FA Plugin
Session Management	Secure cookie-based sessions with refresh	Sessions
Rate Limiting	Configurable limits per endpoint	Rate Limiting
Organizations	Multi-tenant support with roles	Organizations Plugin

Common Patterns

Client Setup with Plugins

// 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

// 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

// 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

Do	Avoid
Require email verification for new accounts	Storing plain-text passwords
Enable rate limiting on auth endpoints	Exposing detailed error messages
Use httpOnly, secure cookies	Using predictable session tokens
Set strong password requirements (12+ chars)	Allowing unlimited login attempts
Implement proper session expiration	Storing sensitive data in JWT
Log authentication events for auditing	Skipping CSRF protection

References

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