The short answer
Firebase Authentication is billed mau-based (+ per-sms). It has a free tier: 50k MAU (basic email/social). The paid plans we list start at ~$0.01–$0.06 / SMS (Phone / SMS authentication).
Plans and prices
| Plan | Price | What it covers |
|---|---|---|
| No-cost tier (Spark / Blaze free allowance) | $0 | First 50,000 monthly active users free for standard auth (email/password, social/federated, anonymous). |
| Standard MAU (Blaze, 50,001–100,000) | $0.0055 / MAU | Graduated per-MAU billing once you exceed the 50k free tier. |
| Standard MAU (100,001–1,000,000) | $0.0046 / MAU | Next graduated pricing band. |
| Standard MAU (1,000,001–10,000,000) | $0.0032 / MAU | Volume band; rate continues to fall to $0.0025/MAU above 10M. |
| Enterprise SSO (SAML / OIDC) | $0.015 / MAU | First 50 SAML/OIDC MAUs free, then $0.015 per MAU (requires Identity Platform upgrade). |
| Phone / SMS authentication | ~$0.01–$0.06 / SMS | Billed per SMS by destination country (US/Canada/India ~$0.01, UK ~$0.04, Brazil ~$0.05, most others ~$0.06); first 10/day free for testing. |
How Firebase Authentication bills you
The pricing model is mau-based (+ per-sms). Google's BaaS-bundled auth with massive scale and SDKs across every mobile/web platform; free to 50k MAU, with Identity Platform for enterprise SSO. Best suited to: mobile/web auth inside firebase.
What to watch for on the bill
- Enterprise features (SAML/OIDC, MFA, SLA, real support) require the paid Identity Platform tier
- Per-SMS phone-auth costs can climb quickly for high-volume or international apps, and have been targets of SMS-pumping abuse
- Support is thin on the free tier; edge cases outside the docs can be hard to resolve
The pricing page we read
Source: https://cloud.google.com/identity-platform/pricing. Prices change, so confirm there before you commit.
Compare Firebase Authentication with alternatives
- Auth0 vs Firebase Authentication pricing
- Firebase Authentication vs WorkOS pricing
- Firebase Authentication vs Clerk pricing
Other authentication & identity apis: Auth0, WorkOS, Clerk, Stytch, Supabase Auth.
Looking at quality rather than price? See the Firebase Authentication score on APIbenchmarks. Full entry: Firebase Authentication pricing.