Clerk vs Lucia for Solo Developers

Quick Comparison

Clerk Overview

Clerk is a managed authentication service that gives you pre-built UI components and a complete auth backend. Install the package, add <SignIn /> and <UserButton /> to your React app, and you have production-ready authentication with social logins, email/password, MFA, and session management. The whole setup takes about 15 minutes.

The management dashboard is solid. You see all your users, their sessions, login methods, and account details in a clean interface. User management features like banning, impersonation, and metadata editing are built in. Organizations with roles and permissions are available for B2B applications.

The free tier covers 10,000 monthly active users, which is more than enough for most solo developer projects in their early stages. Clerk handles the auth infrastructure, session management, token rotation, and security updates. You focus on your product.

Lucia Overview

Lucia is an open-source auth library that provides the building blocks for implementing authentication in your application. It's not a service or a platform. It's code that runs in your project, using your database, under your complete control.

Lucia handles session management, cookie handling, and provides adapters for various databases (PostgreSQL, MySQL, SQLite, MongoDB, and more). You implement the actual authentication logic: password hashing, OAuth flows, email verification. Lucia gives you the framework; you fill in the specifics.

The library is framework-agnostic and works with Next.js, SvelteKit, Astro, Express, and other JavaScript/TypeScript environments. It's intentionally minimal: no UI components, no user management dashboard, no hosted infrastructure. Everything runs on your stack, in your database.

Important note: Lucia's author announced the project is in maintenance mode and recommends using the underlying patterns directly. The library still works, but long-term you may want to understand the session management patterns it teaches rather than depending on the library itself.

Key Differences

Build vs. buy. Clerk is a managed service you integrate. Lucia is a library you build with. With Clerk, auth is "done" in 15 minutes. With Lucia, you spend hours implementing login forms, OAuth callbacks, session management, and user profiles. The time difference is significant.

Data ownership. With Lucia, all user data lives in your database. You query it with your ORM, back it up with your tools, and migrate it on your terms. With Clerk, user data lives on Clerk's servers. You access it through their API and dashboard. If Clerk changes pricing or shuts down, migrating users is non-trivial.

UI components. Clerk provides beautiful, pre-built sign-in, sign-up, user profile, and organization components that you drop into your React app. Lucia provides no UI. You design and build every form, every button, every error state. This is extra work but gives you complete design control.

Cost trajectory. Lucia is free forever. No per-user pricing, no monthly fees, no usage limits. Clerk is free up to 10,000 MAU, then $25/month plus per-user charges. For a solo developer building a consumer app that might grow to 50,000 users, the cost difference becomes meaningful.

Maintenance burden. Clerk handles security patches, token rotation, OAuth provider changes, and infrastructure maintenance. With Lucia, you handle all of that. When Google changes their OAuth API, Clerk updates their integration. With Lucia, you update yours.

Vendor lock-in. Lucia has zero lock-in since it's code in your project using your database. Clerk has significant lock-in. Your auth UI, session management, and user data all live in Clerk's ecosystem. Switching auth providers later requires migrating user data and rebuilding all auth flows.

When to Choose Clerk

• Speed matters and you want auth done in 15 minutes, not 15 hours
• You want pre-built UI components that look professional immediately
• You're building with React/Next.js where Clerk's integration is seamless
• You don't want to think about session management, token rotation, or security patches
• Your project is early-stage and 10,000 free MAU gives you plenty of runway

When to Choose Lucia

• You want complete control over your auth implementation and user data
• You can't afford per-user pricing at scale (or on principle)
• You want zero vendor dependency for a critical system like authentication
• You're building with a non-React framework where Clerk's components don't apply
• You want to learn how authentication actually works at a fundamental level

The Verdict

For solo developers who need to ship fast, Clerk is the pragmatic choice. The 15-minute setup, pre-built components, and managed infrastructure let you focus entirely on your product. Authentication is one of those things that's easy to get wrong and painful to debug, so outsourcing it to a service that handles the security details is smart.

For solo developers who value ownership and long-term cost control, Lucia (or the patterns it teaches) is the more sustainable choice. You invest more time upfront, but you own everything. No vendor dependency, no per-user costs, no surprise pricing changes.

My recommendation for most solo developers: start with Clerk. Get your product to market. If it grows to the point where Clerk's pricing becomes a real line item, you've validated your product and can justify the engineering time to build your own auth. Starting with Lucia when you haven't validated that anyone wants your product is optimizing the wrong thing.