Firebase Auth Alternatives: Beyond Google Lock-In

Last updated: March 2026

Firebase Authentication is the easiest way to add login to a new project. A few lines of code and you have email/password, Google, and Apple sign-in working. For prototypes and small applications, that simplicity is hard to beat.

But Firebase Auth has a ceiling. When your application needs SAML federation for enterprise customers, fine-grained authorization policies, SCIM provisioning, or custom authentication flows beyond what Firebase triggers allow, you hit limits. And because Firebase stores your user data in Google’s infrastructure with Google’s schema, migrating later is harder than it should be.

This guide compares five Firebase Auth alternatives. For each, we cover pricing, self-hosting options, enterprise features, and the practical migration path from Firebase.

Why Teams Outgrow Firebase Auth

The triggers for migration are usually specific:

1. Enterprise sales. A prospective customer requires SAML SSO. Firebase Auth does not support acting as a SAML IdP. The Firebase Identity Platform upgrade adds SAML/OIDC support as a Service Provider, but not as an Identity Provider.

2. User management at scale. Firebase provides basic user listing and search. It does not support custom user attributes in the user record natively (you store them in Firestore), does not have groups or roles built-in, and does not support SCIM for automated provisioning.

3. Authorization. Firebase Auth handles who you are but not what you can do. Authorization logic lives in Firestore Security Rules or Cloud Functions. There is no built-in RBAC, ABAC, or policy engine.

4. Compliance. Some regulations require that authentication data reside in specific regions. Firebase Auth has limited region selection. SOC 2 and HIPAA customers often need dedicated infrastructure with audit trails that Firebase’s shared infrastructure does not provide.

5. Cost at scale. Firebase Auth is free up to 50,000 MAUs for phone auth and standard providers. But SMS verification, Identity Platform features (SAML, OIDC, multi-tenancy, blocking functions), and support plans add up.

The Alternatives

1. Keycloak (Self-Hosted or Managed via Skycloak)

Keycloak is the most mature open-source identity platform. Originally developed by Red Hat, it provides enterprise IAM features that Firebase Auth does not offer: SAML IdP, OIDC provider, identity brokering, user federation (LDAP/AD), and fine-grained authorization.

Pricing:

• Self-hosted: Free (Apache 2.0 license). Infrastructure costs vary by deployment; a two-node cluster on a cloud provider typically runs $150-400/month.
• Managed via Skycloak: Predictable monthly pricing with no per-MAU charges. Includes hosting, backups, monitoring, and support.

Self-hosting options:

• Docker, Kubernetes (with the Keycloak Operator), or bare metal
• Any cloud provider (AWS, GCP, Azure) or on-premises
• PostgreSQL or MySQL for the database

Enterprise features Firebase lacks:

• SAML 2.0 Identity Provider (accept SAML AuthnRequests from any SP)
• SCIM 2.0 for automated user provisioning
• RBAC with realm roles, client roles, and composite roles
• Fine-grained authorization with UMA 2.0
• User federation with LDAP and Active Directory
• Custom authentication flows (visual flow editor, no code required for many scenarios)
• Multi-factor authentication with TOTP, WebAuthn/Passkeys, SMS, email OTP
• Audit logging with event listeners
• Session management with configurable timeouts and concurrent session limits
• Branding/theming with full template control
• Identity provider brokering (connect to any OIDC/SAML provider)

Migration path from Firebase:

Keycloak provides a comprehensive Admin REST API that can import users:

# Export users from Firebase
firebase auth:export users.json --format=json

# Import each user into Keycloak (simplified example)
for user in $(cat users.json | jq -c '.users[]'); do
  email=$(echo $user | jq -r '.email')
  name=$(echo $user | jq -r '.displayName // empty')

  curl -X POST -H "Authorization: Bearer $ADMIN_TOKEN" 
    -H "Content-Type: application/json" 
    "https://keycloak.example.com/admin/realms/myrealm/users" 
    -d "{
      "username": "$email",
      "email": "$email",
      "firstName": "$(echo $name | cut -d' ' -f1)",
      "lastName": "$(echo $name | cut -d' ' -f2-)",
      "enabled": true,
      "emailVerified": true,
      "requiredActions": ["UPDATE_PASSWORD"]
    }"
done

Firebase does not export password hashes in a format other systems can use (they use a modified scrypt implementation). You have two migration strategies:

Lazy migration: Keep Firebase active during a transition period. When a user logs in, authenticate against Firebase, capture the password, and create the credential in Keycloak. Implement this with a custom Keycloak User Storage SPI.

Forced reset: Import all user profiles into Keycloak with UPDATE_PASSWORD as a required action. Users set a new password on first login.

Best for: Teams that need enterprise features, want to avoid vendor lock-in, need on-premises or specific-region deployment, or want predictable pricing without per-MAU charges.

2. Supabase Auth

Supabase Auth is part of the Supabase platform (the open-source Firebase alternative). It provides authentication built on PostgreSQL’s Row Level Security (RLS).

Pricing:

• Free: 50,000 MAUs
• Pro: $25/month (100,000 MAUs included)
• Team: $599/month
• Enterprise: Custom pricing

Self-hosting options:

• Docker (self-hosted Supabase stack)
• Helm charts for Kubernetes
• The full Supabase platform is open source (MIT license for the core)

Enterprise features:

• Email/password, magic link, phone, social login
• Row Level Security integration (authorization at the database level)
• Multi-factor authentication (TOTP)
• Custom SMTP for email
• SSO with SAML 2.0 (Enterprise plan)
• Hook functions for custom logic

What it lacks vs Keycloak:

• No SAML IdP capability (only SAML as a consumer on Enterprise)
• No SCIM support
• No LDAP/AD federation
• No fine-grained authorization policies (relies on RLS)
• Limited custom authentication flow support
• No identity brokering

Migration path from Firebase:
Medium difficulty. Supabase provides a gotrue API that can import users. Social login provider configuration is similar between Firebase and Supabase. Password migration has the same challenges as any Firebase migration.

Best for: Teams already using or considering Supabase for their backend, building applications where database-level authorization (RLS) is a natural fit, or wanting an open-source Firebase replacement.

3. Clerk

Clerk is a developer-focused authentication platform that provides pre-built UI components and a modern developer experience.

Pricing:

• Free: 10,000 MAUs
• Pro: $25/month + $0.02/MAU beyond 10,000
• Enterprise: Custom pricing

Self-hosting options:

• None. Clerk is SaaS-only.

Enterprise features:

• Pre-built sign-in/sign-up components (React, Next.js, Remix)
• Organization management (multi-tenancy)
• SAML SSO (Pro plan)
• MFA (TOTP, SMS, backup codes)
• User impersonation
• Webhooks for event handling
• B2B features (organization invitations, roles)

What it lacks vs Keycloak:

• No self-hosting option
• No SCIM support
• No LDAP/AD federation
• No custom authentication flows
• No SAML IdP capability
• Vendor lock-in to Clerk’s infrastructure
• Per-MAU pricing adds up at scale

Migration path from Firebase:
Low difficulty. Clerk provides import APIs and handles the common Firebase user schema well. Clerk’s UI components mean less custom code to write.

Best for: Small to medium React/Next.js teams that want the fastest possible integration with minimal custom code and do not need enterprise features like SAML IdP or SCIM.

4. Auth0 (Okta)

Auth0 is the most established managed identity platform. It is a direct Firebase Auth replacement for teams willing to pay for a SaaS solution with comprehensive features.

Pricing:

• Free: 25,000 MAUs
• Essentials: From $35/month
• Professional: From $240/month
• Enterprise: Custom pricing

Auth0’s pricing scales per MAU and adds costs for advanced features (adaptive MFA, organizations, attack protection).

Self-hosting options:

• None for standard plans. Private Cloud deployment is available on Enterprise plans.

Enterprise features:

• Extensive SDK ecosystem
• Actions (serverless hooks in the auth pipeline)
• Organizations (B2B multi-tenancy)
• SAML, OIDC, WS-Federation
• Adaptive MFA
• Breached password detection
• User migration connections

What it lacks vs Keycloak:

• No true self-hosting (Private Cloud is managed by Okta)
• Per-MAU pricing becomes expensive at scale
• SCIM and LDAP features require Enterprise plan
• Vendor lock-in to Okta’s infrastructure

Migration path from Firebase:
Low difficulty. Auth0 provides automatic migration connections that authenticate against Firebase on first login and store the password hash locally. This is the smoothest migration path among the alternatives.

Best for: Teams with budget for SaaS pricing that want a mature, well-documented platform with extensive integrations.

For a detailed Auth0 comparison, see Keycloak vs Auth0 Comparison Guide.

5. Appwrite

Appwrite is an open-source backend-as-a-service platform that includes authentication as one of its core services.

Pricing:

• Self-hosted: Free (open source, BSD license)
• Cloud Free: 75,000 MAUs
• Cloud Pro: $15/month (200,000 MAUs)
• Cloud Scale: $599/month

Self-hosting options:

• Docker (single command setup)
• Any cloud provider or on-premises

Enterprise features:

• Email/password, magic link, phone, social login (35+ providers)
• Anonymous sessions
• Team and role management
• MFA (TOTP)
• Custom SMTP
• Session management

What it lacks vs Keycloak:

• No SAML support (neither IdP nor SP)
• No OIDC provider capability (Appwrite issues its own session tokens, not JWTs)
• No SCIM support
• No LDAP/AD federation
• No fine-grained authorization policies
• No identity brokering
• No custom authentication flows

Migration path from Firebase:
Medium difficulty. Appwrite’s user management API can import user profiles. Password migration requires the same lazy migration or forced reset approach as other alternatives.

Best for: Teams building full-stack applications who want an open-source alternative to Firebase’s entire backend (database, storage, functions, auth), not just authentication.

Feature Comparison Table

Feature	Firebase Auth	Keycloak	Supabase Auth	Clerk	Auth0	Appwrite
Open source	No	Yes	Yes	No	No	Yes
Self-hosting	No	Yes	Yes	No	No	Yes
OIDC provider	Yes (limited)	Yes	No	No	Yes	No
SAML IdP	No	Yes	No	No	Yes	No
SAML SP	Yes (paid)	Yes	Enterprise	Pro	Yes	No
SCIM	No	Yes	No	No	Enterprise	No
LDAP/AD	No	Yes	No	No	Enterprise	No
MFA	SMS, TOTP	TOTP, WebAuthn, SMS, email	TOTP	TOTP, SMS	TOTP, SMS, WebAuthn, push	TOTP
RBAC	Custom claims	Built-in	RLS-based	Organizations	Yes	Teams/roles
Custom auth flows	Blocking functions	Visual editor	Hooks	No	Actions	No
Audit logging	Cloud Logging	Built-in events	Postgres logs	Dashboard	Dashboard + streams	Built-in
Multi-tenancy	Projects	Realms + Orgs	Organizations	Organizations	Organizations	Projects
Pricing model	Free + per MAU	Free / managed	Free + per MAU	Free + per MAU	Free + per MAU	Free / per org
SDK ecosystem	Broad	Java, JS, Python	JS, Dart, Swift	React, Next.js	Very broad	Broad

Cost Comparison at Scale

For an application with 100,000 MAUs:

Provider	Estimated Monthly Cost
Firebase Auth (Identity Platform)	$275-550
Keycloak self-hosted	$150-400 (infra only)
Keycloak managed (Skycloak)	See pricing
Supabase Auth (Pro)	$25
Clerk (Pro)	$1,825
Auth0 (Professional)	$800+
Appwrite (Cloud Pro)	$15

Note: These are base costs. Enterprise features (SAML, SCIM, advanced MFA) add significantly to Auth0 and Clerk pricing. Supabase and Appwrite prices are for the platform, not just auth. Use the IAM ROI Calculator to model costs for your specific usage.

Making the Decision

Choose Keycloak/Skycloak if you need enterprise IAM features (SAML IdP, SCIM, LDAP federation, fine-grained authorization), want to self-host or use managed hosting without per-MAU pricing, or need to support B2B enterprise customers with SSO requirements. Skycloak removes the operational burden of self-hosting while keeping all features.

Choose Supabase Auth if you are building on the Supabase platform and want authentication that integrates directly with PostgreSQL Row Level Security. It is the most natural choice if Supabase is already your backend.

Choose Clerk if you are building a React/Next.js application, want pre-built UI components, and your authentication needs are standard (email/password, social login, basic MFA). Be aware of per-MAU costs at scale.

Choose Auth0 if you need a fully managed SaaS platform with the broadest SDK ecosystem and are prepared for per-MAU pricing. Auth0’s automatic migration connection makes it the easiest migration target from Firebase.

Choose Appwrite if you want an open-source Firebase replacement for the full backend stack, not just authentication, and your authentication needs are straightforward.

Stay with Firebase Auth if you are building a small application, are deeply integrated with the Firebase/Google Cloud ecosystem, and do not need enterprise features like SAML or SCIM.

Migration Checklist

Regardless of which alternative you choose:

• [ ] Export all Firebase user profiles (email, display name, phone, providers)
• [ ] Map Firebase custom claims to the new system’s role/permission model
• [ ] Plan password migration (lazy migration or forced reset)
• [ ] Update social login provider configurations (Google, Apple, GitHub OAuth apps)
• [ ] Migrate email templates (verification, password reset)
• [ ] Update client-side authentication code (SDK swap)
• [ ] Test all authentication flows (login, registration, password reset, social, MFA)
• [ ] Run parallel systems during the migration window
• [ ] Monitor login success rates post-migration
• [ ] Decommission Firebase Auth after the migration window closes

For Keycloak-specific migration, the Keycloak Docker Compose Generator helps set up a local test environment for migration testing before going to production.

---

Ready to move beyond Firebase Auth? Skycloak provides managed Keycloak with enterprise IAM features, predictable pricing, and SOC 2 compliance. Check our pricing or explore our documentation to plan your migration.