vs
Firebase vs NextAuth.js (Auth.js)
Side-by-side comparison of Firebase and NextAuth.js (Auth.js).
Quick summary
Firebase — Google's app development platform. Firebase is Google's mobile and web app development platform offering realtime database, authentication, hosting, and serverless functions.
NextAuth.js (Auth.js) — Authentication for the web. Auth.js (formerly NextAuth) is a free open-source authentication library for Next.js and other frameworks.
Feature comparison
| Feature | Firebase | NextAuth.js (Auth.js) |
|---|---|---|
| Pricing model | Freemium | Free |
| Starting price | Pay as you go | Free |
| Free tier | Yes | Yes |
| Open source | No | Yes |
| Auth | Yes | — |
| Storage | Yes | — |
| Database | Firestore (NoSQL) | — |
| Realtime | Yes | — |
| Free Tier | Spark plan (generous) | Self-hosted |
| Self-hosted | No | Yes |
| Edge Functions | Yes | — |
| Row Level Security | No | — |
| MFA | — | No |
| SAML/SSO | — | No |
| Pre-built UI | — | No |
| Social Login | — | Yes |
| Organizations | — | No |
Firebase
Google's app development platform
Pros
- Battle-tested at massive scale
- Excellent mobile SDKs
- Deep Google Cloud integration
Cons
- Vendor lock-in with Firestore
- Costs can surprise you at scale
- NoSQL-only data model
NextAuth.js (Auth.js)
Authentication for the web
Pros
- Free and open source
- Huge provider catalog
- Self-hosted
Cons
- No built-in MFA/orgs
- You build your own UI
- Docs can be rough
Which should you choose?
Choose Firebase if a free tier is important for your stage. Choose NextAuth.js (Auth.js) if you value open source and want the option to self-host, and a free tier is important for your stage.
Frequently asked questions
Which is better, Firebase or NextAuth.js (Auth.js)?
There is no universal “better.” For most teams, NextAuth.js (Auth.js) is the safer default because NextAuth.js (Auth.js) is open source, which means you can self-host and avoid vendor lock-in. Firebase is proprietary. For edge cases, the comparison table above highlights where each tool wins.
Is Firebase cheaper than NextAuth.js (Auth.js)?
Firebase starts at Pay as you go, while NextAuth.js (Auth.js) starts at Free. Exact costs depend on usage — check both vendors' calculators before committing.
Can I migrate from Firebase to NextAuth.js (Auth.js)?
Migration difficulty depends on how deeply Firebase-specific features (APIs, SDK conventions, data schemas) are baked into your app. Most backend as a service migrations take days to weeks. Both vendors typically publish migration guides — check their docs.
Is Firebase or NextAuth.js (Auth.js) open source?
NextAuth.js (Auth.js) is open source; Firebase is a proprietary managed service.
Does Firebase or NextAuth.js (Auth.js) have a free tier?
Both Firebase and NextAuth.js (Auth.js) offer a free tier.
Which is best for startups and indie hackers?
Startups usually optimize for the lowest friction to ship and the cheapest possible free tier. The one with the most generous free tier here is Firebase. For production workloads, revisit the trade-offs in the feature table above.