Lucia
Lightweight TypeScript auth library. Library-not-framework — minimal opinions, BYO everything.
VISIT LUCIAQuick facts
- CategoryLibrary / OSS
- LanguageTypeScript
- PricingOpen source
- LicenseMIT
- Created2021
- GitHub stars9.7k
- HIPAA-eligibleNo
- SSO / SAMLLimited / paid
What it is
Lucia is the lightweight library-not-framework alternative. Session-based auth primitives, BYO database adapter, BYO password hashing, BYO UI. The opposite of Clerk in design philosophy — minimal opinions, maximum flexibility, much smaller surface area.
Best for
- Teams that want auth as a library, not a service
- Apps with non-standard requirements (custom session shapes, custom hashing)
- TypeScript developers who prefer composing primitives
When not to pick it
Skip Lucia for teams that want auth solved as a product. Skip for projects with a tight timeline; you build a lot yourself.
My take
Lucia is the right pick when you want auth primitives, not an auth product. Smaller community than Auth.js, cleaner internals.
Links
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If Lucia is your pick — the next conversation is short
The 30-min call is where your auth choice becomes a real architecture, a migration plan if you are switching, and a price range you can take to your stakeholders. Describe your stack, your scale, your compliance constraints. I tell you whether Lucia is genuinely your fit.