🔐 Authentication Comparison
Clerk vs Lucia
A detailed comparison to help you choose the right tool for your needs.
Last updated: 2026-02-06
Clerk
Free up to 10k MAU, from $25/mo
Strengths
- + Pre-built React components for auth that actually look good out of the box
- + 10,000 monthly active users free — most startups run free for months
- + Handles the hard stuff: MFA, social login, organization management
Weaknesses
- − Vendor lock-in is real — migrating away from Clerk means rebuilding auth
- − Pricing jumps at scale (10k+ MAU) can surprise you
- − React-focused — less polished for non-React stacks
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 Clerk if you want
- → Pre-built React components for auth that actually look good out of the box
- → 10,000 monthly active users free — most startups run free for months
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
Clerk
Drop-in auth with pre-built UI components — sign-up, sign-in, and user management in minutes
Clerk gives you a complete auth system without building one. Install the package, drop in the sign-up component, and you have Google login, email/password, MFA, and user profiles working. The UI components look professional without any styling work.
The 10,000 MAU free tier is genuinely generous — most early startups will not outgrow it for months. The concern is lock-in: once your app is wired to Clerk’s components and APIs, moving to something else is a significant rewrite. If you are validating an idea and need auth fast, Clerk is the fastest path. If you are building something you expect to maintain for years, consider whether the convenience is worth the dependency.
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.
Stay ahead of the curve
Get weekly picks of the best tools for solo founders, plus tips on building with AI.
Join solo founders getting weekly tool recommendations. No spam, unsubscribe anytime.
Keep exploring
Related comparisons
Still deciding?
Explore more Authentication tools
Browse the full category or discover tools across all categories.