Auth0 vs Firebase Authentication

Auth0 vs Firebase Authentication

Neither is better for everyone. Auth0 suits teams needing a standalone identity provider. Firebase Authentication suits apps already on Firebase or Google Cloud.

Auth0 vs Firebase Authentication at a glance

This page compares Auth0 and Firebase Authentication using only what the sources below say about each. Where one is the better pick for a situation, we say which and why.

We read each source on 2026-11-05. Prices and limits change often, so confirm on the vendor's own page before you buy. A figure marked "one source only" was not matched by a second publisher.

When to pick each one

Pick Auth0 if it matches your situation

Choose Auth0 over Firebase Authentication for teams needing a standalone identity provider.

Pick Firebase Authentication if it matches your situation

Choose Firebase Authentication over Auth0 for apps already on Firebase or Google Cloud.

Limits and things to check

Auth0

• Auth0's FAQ states that beyond 25,000 users a paid plan is needed.^[1]
• Auth0's pricing page lists custom tiers for Essentials and Professional external active users.^[1]
• G2 lists separate B2B plans at $150 per month (Essentials) and $800 per month (Professional).^[3] One source only.

Firebase Authentication

• Google's Identity Platform pricing page says it is no-cost up to 50K MAUs.^[2]
• Phone and multi-factor authentication are charged per message with a region-specific rate table.^[2]
• SMS rate sources conflict: one puts US and Canada at $0.01 per SMS, another cites $0.04 in us-central1.^[4] One source only.

Pricing as reported

Auth0

Pricing as reported for Auth0:

• Free: $0 (Up to 25,000 monthly active users) ^[1]
• Essentials: $35 per month (Most sources say up to 500 MAU; G2 lists up to 5,000 MAU. Disagreement) ^[3] One source only, so confirm it on the vendor page.
• Professional: $240 per month (Most sources say 500 MAU; G2 says up to 1,000 MAU. Disagreement) ^[3] One source only, so confirm it on the vendor page.

Firebase Authentication

Pricing as reported for Firebase Authentication:

• Identity Platform: $0 up to 50,000 MAU (SAML/OIDC allowance is 50 MAUs; phone and multi-factor users are charged per message sent, with the first ten SMS per day free) ^[2]

Where Continuum fits

We make Continuum Supabase Security Review. Weigh what we say here with that in mind. The tools above are the better choice when you want software you run yourself; ours is the better choice when you want a person to do or read the work.

Continuum Supabase Security Review (ours)

A human review of a Supabase app covering row level security policies, key exposure, storage rules, auth config and service-role usage.^[5]

What our own page says:

• It returns ranked findings with corrected SQL and a proof for each, in 48 hours.^[5]

Limits and things to check:

• It is a manual review of one app, not a continuous monitor.^[5]

Pricing as reported for Continuum Supabase Security Review:

• Supabase Security Review: Quoted on the page (48 hour turnaround) ^[5]

Suits a team running on Supabase that wants a person to read its policies and keys before launch.

Details on Continuum Supabase Security Review.

Running on Supabase?

Straight answers