Better Auth vs Lucia for SvelteKit
Better Auth and Lucia both answer the same question in a SvelteKit project: how do users sign in? Open source TypeScript auth library that keeps sessions and users in your own database, extended through plugins. No longer a library but a reference that teaches you to implement sessions yourself, with code you copy and own. The real split is ownership: Better Auth runs inside your project and leaves the operational work with you, while Lucia runs the hard parts as a service and takes a dependency in exchange.
Verdict
The real split is ownership: Better Auth runs inside your project and leaves the operational work with you, while Lucia runs the hard parts as a service and takes a dependency in exchange. For SvelteKit specifically, both are supported, so let the tradeoff above decide rather than the framework.
Pick Better Auth if
- ✓User and session tables sit in your database, so joins are ordinary SQL.
- ✓Plugin system covers passkeys, two factor and organizations without vendor lock-in.
- ✓Fully typed API surface, so misuse usually shows up at compile time.
Pick Lucia if
- ✓You end up understanding exactly how your session cookies and tokens work.
- ✓Zero dependency to break, deprecate or change licence underneath you.
- ✓Session schema is yours, so it fits whatever data model you already have.
| Comparison | Better Auth | Lucia |
|---|---|---|
| Pricing shape | Free and open source. You pay only for the database and server it runs on. | Free. It is documentation, so there is nothing to buy or subscribe to. |
| Frameworks | Next.js, SvelteKit, Nuxt, Expo | Next.js, SvelteKit |
| In one line | Open source TypeScript auth library that keeps sessions and users in your own database, extended through plugins. | No longer a library but a reference that teaches you to implement sessions yourself, with code you copy and own. |
Pricing described qualitatively because published plans change often. Checked 2026-08-23. Confirm current terms on Better Auth and Lucia.
Better Auth
Strengths
- ✓User and session tables sit in your database, so joins are ordinary SQL.
- ✓Plugin system covers passkeys, two factor and organizations without vendor lock-in.
- ✓Fully typed API surface, so misuse usually shows up at compile time.
- ✓No per-user cost, which makes free tiers and large user bases cheap.
Tradeoffs
- ✗You run and patch the auth code yourself, including security updates.
- ✗Login screens are your responsibility, since the library ships logic not UI.
- ✗Younger project, so APIs still move and older guides go stale quickly.
- ✗Compliance evidence like SOC 2 covers your infrastructure, not a vendor's.
Lucia
Strengths
- ✓You end up understanding exactly how your session cookies and tokens work.
- ✓Zero dependency to break, deprecate or change licence underneath you.
- ✓Session schema is yours, so it fits whatever data model you already have.
- ✓Excellent teaching material even if you eventually pick a different tool.
Tradeoffs
- ✗Copied code means you carry the maintenance and security review forever.
- ✗No package upgrades, so fixes only land if you go looking for them.
- ✗Every provider, reset flow and rate limit is hand-rolled work.
- ✗Hard to justify on a team where nobody wants to own auth internals.
Same pair, different context
Frequently asked questions
Is Better Auth or Lucia better in a SvelteKit project?
Neither is better in the abstract. The real split is ownership: Better Auth runs inside your project and leaves the operational work with you, while Lucia runs the hard parts as a service and takes a dependency in exchange. Decide on the tradeoff you can live with, then stop reading comparisons and ship.
What is the main drawback of Better Auth?
You run and patch the auth code yourself, including security updates. Login screens are your responsibility, since the library ships logic not UI.
What is the main drawback of Lucia?
Copied code means you carry the maintenance and security review forever. No package upgrades, so fixes only land if you go looking for them.
Do Better Auth and Lucia both support SvelteKit?
Yes, both list support for SvelteKit, which is why this comparison exists as a SvelteKit page. SvelteKit moved fast enough that training data contains three incompatible generations of it: Sapper, SvelteKit 1.0, and SvelteKit 2 on Svelte 5.