Feature Guide

How to build
Authentication & User Management

User signup, login, password reset, social auth, MFA, and session management. The foundation of every SaaS.

intermediate
2–4 weeks (manual)
2–5 days (with AI)

Best tools to use

[01]

better-auth

TypeScript-first auth library with plugins for MFA, passkeys, and organizations.

[02]

Clerk

Drop-in auth UI components with user management dashboard. Fastest to implement.

[03]

Supabase Auth

Built into Supabase. Social login, magic links, and RLS integration.

[04]

NextAuth.js (Auth.js)

Open-source, flexible auth for Next.js. Large ecosystem of providers.

[05]

Firebase Auth

Google's auth service. Great for mobile apps and quick prototypes.

Key considerations

  • ✓Always hash passwords with bcrypt or argon2 — never store plaintext
  • ✓Implement rate limiting on login endpoints to prevent brute force
  • ✓Use HTTP-only cookies for session tokens, not localStorage
  • ✓Support social login (Google, GitHub) — reduces signup friction by 30-50%
  • ✓Plan for multi-tenancy early if building B2B SaaS

Common mistakes

  • ✗Rolling your own auth from scratch — use a library
  • ✗Storing JWTs in localStorage (XSS vulnerable)
  • ✗No email verification flow
  • ✗Forgetting password reset token expiration
  • ✗Not handling account linking for social + email signups

Products that nailed this

Clerk
Auth0
Stytch
WorkOS

Related features

role based accesssubscription billingteam management

Skip the research.

SassCloner generates implementation specs for authentication & user management — including database schema, API routes, and UI components. Paste into Cursor and start building.

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