Clerk is a closed-source, developer-focused authentication platform with prebuilt UI components for React, Next.js, and Remix. It's free up to 50,000 monthly active users, but pricing beyond that scales per MAU and can reach into the thousands per month at larger user bases, with user data managed on Clerk's infrastructure.
Hanko is the open-source option, built around passkey-first authentication with SSO, MFA, and embeddable web components — self-hostable so user identity data stays on your own infrastructure.
FAQ
Is there a free, open-source alternative to Clerk?
Yes. Hanko is open source and free to self-host.
What's the best open-source alternative to Clerk?
Hanko is the option to evaluate — it's built passkey-first, with SSO and MFA support, and avoids Clerk's per-MAU pricing since you're self-hosting.
What are the top open-source alternatives to Clerk?
Browse all open-source alternatives to Clerk above, or explore the full Security category for more options.