🔐 Authentication Comparison
Auth0 vs Lucia
A detailed comparison to help you choose the right tool for your needs.
Last updated: 2026-02-06
Auth0
Free up to 7k MAU, from $23/mo
Strengths
- + Supports every auth method: social, email, passwordless, SAML, LDAP
- + 7,000 MAU free tier is solid for early-stage products
- + Battle-tested at scale — used by thousands of companies
Weaknesses
- − Way more complex than you need if you just want Google login
- − Pricing tiers jump steeply — you can go from free to $240/mo quickly
- − Documentation is extensive but can be hard to navigate
Lucia
Free and open source
Strengths
- + Completely free, no MAU limits, no vendor lock-in — it is just a library
- + Works with any database (Postgres, MySQL, SQLite, MongoDB) and any framework
- + Tiny footprint — no external services, your auth data stays in your own database
Weaknesses
- − You build everything yourself — no pre-built login UI, no hosted dashboard
- − Requires solid understanding of sessions, cookies, and auth security
- − Maintained primarily by one developer — smaller bus factor than corporate-backed tools
The verdict
Which one is right for you?
Choose Auth0 if you want
- → Supports every auth method: social, email, passwordless, SAML, LDAP
- → 7,000 MAU free tier is solid for early-stage products
Choose Lucia if you want
- → Completely free, no MAU limits, no vendor lock-in — it is just a library
- → Works with any database (Postgres, MySQL, SQLite, MongoDB) and any framework
In depth
About each tool
Auth0
Enterprise-grade auth that handles every login method — from social login to SAML SSO
Auth0 is the auth provider you pick when your app needs enterprise features — SAML SSO, LDAP, MFA policies, organization management. It supports every login method that exists and has been battle-tested by companies from startups to Fortune 500s. It is now part of Okta.
For solo founders, Auth0 is often more than you need. If you just want social login and email/password, Clerk or Supabase Auth is simpler and faster to set up. Where Auth0 earns its complexity is when you need to sell to companies that require SSO, or when compliance demands specific auth flows. Start with something simpler and migrate to Auth0 when enterprise requirements show up.
Lucia
Lightweight open-source auth library that gives you full control over your authentication logic
Lucia is auth stripped down to its essentials. It is a TypeScript library that handles session management and gives you helpers for password hashing, OAuth, and token generation. There is no hosted service, no dashboard, no per-user pricing — just code that runs in your app, storing sessions in whatever database you already use.
This makes Lucia the opposite of Clerk or Auth0. You get maximum control and zero recurring costs, but you write more code. You need to build your own login forms, handle email verification flows, and set up OAuth callbacks yourself. For developers comfortable with auth concepts, Lucia is rewarding — your auth is simple, portable, and costs nothing at any scale. For solo founders who want auth done in an afternoon without thinking about security details, a managed service like Clerk or Firebase Auth is a safer bet.
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