Understanding Firebase Authentication pricing can be confusing. Between the generous free tier, Monthly Active Users (MAUs), and premium features hidden in Google Cloud Identity Platform, it’s hard to know what you’ll actually pay. Whether you’re launching a new app or scaling an existing one, getting your authentication costs right is crucial.
At MetaCTO, we’ve helped countless startups and established companies navigate these complexities as part of our mobile app development services. This guide provides a clear, up-to-date breakdown of all Firebase Auth costs for 2025. We’ll cover the free tier, how MAUs are calculated, SMS pricing, and exactly what happens when you need to upgrade.
TL;DR: Firebase Authentication is free for the first 50,000 Monthly Active Users (MAUs) for basic email/password and social logins. You only pay for Phone Authentication (SMS) or if you exceed 50,000 MAUs, which requires upgrading to the Google Cloud Identity Platform.
Do I Need To Pay For Firebase Auth Infographic
Designer Instructions
Create a simple, visually engaging flowchart that answers the main question. Use large 'Yes' and 'No' paths with icons. Flow: Start with 'Are you only using Email, Google, Facebook, etc. to log in users?' If Yes: 'Do you have LESS than 50,000 Monthly Active Users?' If Yes: 'It's 100% FREE!' If No: 'You pay per user after 50k.' If original answer is No: 'Are you using Phone/SMS Authentication?' If Yes: 'You pay per SMS sent, starting from $0.01.'
Firebase’s Free Tier vs. Paid Tier (Identity Platform)
Firebase Auth’s pricing is split into two main products: the standard Firebase Authentication service (with its generous free tier) and the more powerful Google Cloud Identity Platform, which you are automatically upgraded to when you exceed the free tier limits.
Free Tier vs Paid Tier Comparison Infographic
Designer Instructions
Create a visual breakdown of what's included in the free tier vs. what requires payment (upgrading to Identity Platform). Two-column layout: 'FREE TIER (Up to 50,000 Users)' and 'PAID TIER (Identity Platform)'. Left: Large '50,000 MAUs' text, icons for Email/Google/Facebook/Apple with 'Included' text. Right: '>50,000 MAUs' text, icons for SAML/OpenID Connect/MFA with 'Premium Feature' text. Small section at bottom: *Phone/SMS auth has costs on all tiers.
Here’s a clear, detailed comparison of what you get with each.
| Feature | Firebase Auth (Free Tier) | Identity Platform (Paid Tier) |
|---|---|---|
| Monthly Active Users (MAUs) | Up to 50,000 | First 50,000 are free, then tiered pricing |
| Standard Auth Providers | Email/Password, Google, Apple, Facebook, Twitter, GitHub | ✅ Included |
| Anonymous Auth | ✅ Included | ✅ Included |
| Phone Auth (SMS) | Paid per verification | Paid per verification (same rates) |
| Advanced Auth Providers | ❌ Not Available | ✅ SAML, OpenID Connect (OIDC) |
| Multi-Factor Auth (MFA) | ❌ Not Available | ✅ Included |
| Service Level Agreement (SLA) | ❌ Not Available | ✅ 99.95% Uptime |
| Custom Email Templates | ✅ Basic Customization | ✅ Advanced Customization via own SMTP server |
| Blocking Functions | ✅ Included | ✅ Included |
What are the Limits of the Firebase Auth Free Tier?
The free tier is designed for small to medium-sized apps and includes:
- Up to 50,000 Monthly Active Users (MAUs).
- Authentication Methods: Email & Password, Google, Facebook, Twitter, GitHub, Apple, Microsoft, and Yahoo sign-ins.
- Other Features: Secure account management, password reset flows, and basic email verification customization.
You will only be forced to upgrade to the paid Identity Platform tier if your app grows beyond 50,000 MAUs in a month.
How Are Monthly Active Users (MAUs) Calculated?
A “Monthly Active User” is one of the most important concepts in Firebase pricing.
Definition: An MAU is any user account that signs in or is created within a calendar month.
- First-time sign-in: When a user signs in for the first time during a month, they are counted as one MAU.
- Subsequent sign-ins: That same user can sign in a thousand more times during that same month, and they will still only count as one MAU.
- New Month, New Count: The counter resets on the first of every month.
This means you are not charged per sign-in, but per unique user that authenticates each month.
Firebase Phone Authentication Pricing (SMS & OTP Costs)
Phone Authentication (verifying a user’s phone number via an SMS code) is the one feature that is NOT free, even within the 50,000 MAU free tier.
You are charged per verification sent. The price varies significantly by country.
- United States, Canada, India: $0.01 per verification
- United Kingdom: $0.04 per verification
- Brazil: $0.05 per verification
- All other countries: $0.06 per verification
World Map of SMS Authentication Costs Infographic
Designer Instructions
Create a world map highlighting the different costs for phone authentication in key regions. Use large, easy-to-read price tags pointing to different countries/continents: $0.01 pointing to the USA and India, $0.04 pointing to the UK, $0.06 covering a large area labeled 'Most of the World'. Include a simple formula at the bottom: (Your Users) x (Cost per SMS) = Your Monthly Bill.
Important: These costs can add up quickly. If you plan to heavily use phone authentication, be sure to budget for these costs. You must have a billing account enabled on your Google Cloud project to use this feature.
What Happens When You Exceed 50,000 MAUs?
This is the most critical pricing question. Once your 50,001st user signs in during a month, your project is automatically upgraded to the Google Cloud Identity Platform paid plan. You don’t lose access, but you start paying.
The pricing is tiered:
| Monthly Active Users (MAUs) | Price per MAU |
|---|---|
| 0 - 50,000 | Free |
| 50,001 - 999,999 | $0.0025 |
| 1,000,000+ | $0.0015 |
Example Calculation: If your app has 70,000 MAUs in a month:
- The first 50,000 MAUs are free.
- You pay for the remaining 20,000 MAUs.
- Cost: 20,000 * $0.0025 = $50 for the month.
Firebase Authentication Alternatives
While Firebase Auth is a market leader, it’s not the only option. Here are a few alternatives to consider:
- Supabase Auth: A popular open-source alternative that can be self-hosted. It offers a similar feature set.
- Auth0: A very powerful and flexible identity platform, but its free tier is much more limited (7,500 MAUs) and it can become expensive quickly.
- Clerk: A developer-focused auth solution with a generous free tier (10,000 MAUs) and beautiful pre-built components.
Choosing the right authentication platform is a critical technical and business decision. At MetaCTO, we provide unbiased guidance as part of our Fractional CTO services to help you make the most cost-effective choice for your specific situation.
When to Seek Expert Help
While Firebase Authentication is designed to be straightforward, implementing a secure, scalable, and user-friendly authentication system can still be complex. If you’re managing a large user base, migrating from another system, or need to integrate enterprise features like SAML or OIDC, partnering with an expert can save you time and prevent costly mistakes.
At MetaCTO, we specialize in building robust applications using cutting-edge technologies like Firebase. Our services, from rapid MVP development to full-scale mobile app development, cover everything from initial architecture to long-term maintenance, ensuring your app’s foundation is secure and built to scale.
Frequently Asked Questions (FAQ)
What is the difference between Firebase Authentication and Identity Platform?
Firebase Authentication is the developer-facing product name with the generous free tier. Google Cloud Identity Platform is the underlying enterprise-grade service that powers it. For all practical purposes, when you outgrow the Firebase free tier, you are simply moved to the paid tier of Identity Platform. It provides the same core functionality plus advanced features like SAML, OIDC, and an SLA.
Is there a free tier for Phone Authentication?
No. Phone (SMS) authentication is the only feature that costs money from the very first use. Google has to pay telecommunication carriers to send text messages, and that cost is passed on to you. You get 10 free SMS verifications per month for testing purposes on a test phone number, but that's it.
How can I estimate my monthly Firebase Auth costs?
1. **Estimate your MAUs:** How many unique users do you expect to log in each month? If it's under 50,000, your base cost is $0. 2. **Estimate your SMS Verifications:** How many new users will sign up with a phone number? How many will log in using SMS? Multiply that number by the rate for your target countries. 3. **Total Cost = (MAUs above 50k * Tiered Rate) + (Total SMS Verifications * SMS Rate)**
What are some free alternatives to Firebase Authentication?
If your needs are complex or you want to avoid vendor lock-in, several excellent open-source and managed alternatives exist: **Supabase Auth:** A popular open-source alternative that can be self-hosted. It offers a similar feature set. **Auth0:** A very powerful and flexible identity platform, but its free tier is much more limited (7,500 MAUs) and it can become expensive quickly. **Clerk:** A developer-focused auth solution with a generous free tier (10,000 MAUs) and beautiful pre-built components.
Conclusion: Let’s Build Your App the Right Way
For the vast majority of applications, Firebase Authentication is free and powerful. The 50,000 MAU limit is incredibly generous, allowing you to focus on building your product, not your billing plan.
However, as your application grows, so does its complexity. Choosing the right authentication strategy is a critical decision that impacts security, user experience, and your bottom line.
If you’re ready to build a secure, scalable application with a team that understands the modern tech landscape, we’re here to help. Contact MetaCTO today for a free consultation and let’s discuss how we can turn your vision into a reality.