Firebase Authentication alternatives for web app

If you’re looking for Firebase Authentication alternatives for a web app, the best choice depends on whether you want a hosted auth service, open-source/self-hosted, or enterprise-grade identity.

Popular alternatives

1) Auth0

• Best for: Fast setup, social login, enterprise auth, strong docs
• Pros: Very polished, supports OAuth/OIDC/SAML, MFA, RBAC
• Cons: Can get expensive at scale

2) Clerk

• Best for: Modern web apps and great developer experience
• Pros: Beautiful prebuilt UI, easy Next.js/React integration, user management built-in
• Cons: Less flexible for complex enterprise identity setups than Auth0

3) Supabase Auth

• Best for: Apps already using Supabase
• Pros: Open-source, email/password, magic links, OAuth, good pricing
• Cons: Less mature than Auth0 for advanced identity workflows

4) AWS Cognito

• Best for: Apps already on AWS
• Pros: Cheap at scale, integrates with AWS ecosystem, supports social login and MFA
• Cons: Harder to configure and use; developer experience is rougher

5) NextAuth.js / Auth.js

• Best for: Next.js apps wanting flexible authentication
• Pros: Open-source, supports many providers, works well with custom backends
• Cons: Not a full user management service; you need to handle more yourself

6) Keycloak

• Best for: Self-hosted enterprise auth
• Pros: Open-source, supports SSO, OIDC, SAML, MFA
• Cons: Operational overhead, heavier setup

7) Ory (Kratos / Hydra)

• Best for: Self-hosted, security-focused auth
• Pros: Very flexible, modern identity architecture
• Cons: More complex to implement and operate

8) Supabase + custom backend auth

• Best for: Teams wanting control with a managed Postgres stack
• Pros: Easy to combine auth + database + storage
• Cons: Not ideal if you need enterprise identity features

Quick recommendations

• Want easiest replacement for Firebase Auth? → Clerk or Supabase Auth
• Need enterprise features? → Auth0 or Keycloak
• Already on AWS? → Cognito
• Using Next.js and want control? → Auth.js / NextAuth.js
• Want open-source/self-hosted? → Keycloak or Ory

What to compare

When choosing, check:

• Email/password support
• Social login providers
• Magic links / passwordless
• MFA / 2FA
• User management UI
• Custom claims / roles
• SSO / SAML / OIDC
• Pricing at your expected scale
• Self-hosted vs managed
• SDK support for your framework

If you want, I can also give you:

1. a comparison table,
2. the best option for React/Next.js, or
3. a migration path from Firebase Auth.