Today’s developers want to move fast without getting bogged down by backend complexity. Firebase helps make that possible. It’s Google’s Backend-as-a-Service (BaaS) platform, offering everything from authentication and databases to hosting, cloud functions, analytics, and more—all designed to help teams launch quickly and scale reliably.
At the heart of Firebase’s offering is its flexible pricing model. The Spark plan gives you generous free quotas, perfect for prototyping, hobby apps, or early-stage projects. When you’re ready to scale, the Blaze plan kicks in with pay-as-you-go pricing across storage, compute, and bandwidth. That flexibility makes Firebase a go-to choice for everything from solo side projects to production workloads powering millions of users.
But understanding where the free tier ends and the billing starts isn’t always obvious. This guide walks through Firebase’s pricing in detail, breaking down costs by feature, surfacing hidden charges, and comparing it to alternatives like Auth0, Okta, and SuperTokens—so you can make an informed decision before your app hits scale.
What Is Firebase and How Does It Price?
Firebase is Google’s Backend-as-a-Service (BaaS) platform designed to help developers build, ship, and scale applications quickly—without having to manage infrastructure. It includes a broad suite of tools for:
- Authentication
- Databases
- Storage
- Serverless Functions
- Analytics
- Testing
Its core services include:
- Firebase Auth
- Firestore
- Realtime Database
- Cloud Functions
- Cloud Storage
- Hosting
- Crashlytics
- Remote Config
All Firebase services are tightly integrated with the broader Google Cloud ecosystem—making it easier to scale, manage access, and transition to more advanced infrastructure as your app grows.
How Firebase’s Pricing Model Works
When it comes to pricing, Firebase follows a dual-tier model:
Spark Plan (no-cost): This tier offers generous free quotas across many Firebase products, including:
- Email and Social Authentication—Up to 50,000 MAUs.
- SAML/OIDC Authentication—Up to 50 MAUs.
- Firestore and Realtime Database—Free daily read/write limits and storage.
- Cloud Functions and Hosting—Generous usage caps on invocations, storage, and bandwidth.
- Analytics, Messaging (FCM), and Crashlytics—Fully free and unlimited.
It’s ideal for prototyping, early-stage development, or hobby projects where usage remains relatively low.
Blaze Plan (pay-as-you-go): This tier retains all Spark quotas but adds usage-based billing once you exceed them. It also unlocks additional features not available on the free plan, such as phone authentication and Cloud Vision APIs in Firebase ML.
Key products with metered pricing include:
- Firestore and Realtime Database—Pay for reads, writes, deletes, storage, and egress beyond free limits.
- Authentication—Phone authentication is billed per SMS; other methods remain free within MAU thresholds.
- Cloud Storage—Charged by GB stored, GB downloaded, and number of operations.
- Cloud Functions—Billed by invocations, GB-seconds, and CPU-seconds.
- Hosting—Pay for data transfer and storage beyond free daily and monthly caps.
Pricing is granular and based on usage—so costs scale with traffic, not tiers. You only pay for what you use.
A Breakdown of Firebase Pricing Tiers
The table below compares the Spark (free) and Blaze (pay-as-you-go) plans across Firebase’s most commonly used features:
| Feature | Spark (Free) | Blaze (Pay-as-you-go) |
|---|---|---|
| Authentication (Email, Social) | Fully free, up to 50,000 monthly active users (MAUs) | Free up to 50K MAUs, then billed at $0.0055–$0.0025/MAU |
| SAML/OIDC Authentication | Free for up to 50 MAUs (via Identity Platform) | Billed at $0.015/MAU beyond 50 MAUs |
| Phone Authentication (SMS) | Not available | Billed per SMS, typically $0.01–$0.06/SMS depending on region |
| Firestore | 1 GiB storage, 50K reads/day, 20K writes/day, 10 GiB/month egress | Pay per GB stored, operations (read/write/delete), and egress beyond free limits |
| Cloud Functions | 2M invocations/month, 400K/month GB-sec, 200K/month CPU-sec, 5 GB egress | Pay-per-use beyond limits (invocations, compute, egress) |
| Storage and Hosting | 5 GB storage, 360 MB/day transfer (Hosting) | Pay for storage, downloads, and bandwidth at Google Cloud rates |
| Other Products | Analytics, Crashlytics, FCM, Remote Config, Performance Monitoring—all free | Same—fully free and unlimited |
This breakdown gives you a clearer view of what’s truly free—and where usage starts to incur costs as your app scales.
What Does Firebase Actually Cost? (Real-World Examples)
Firebase pricing is usage-based, which means costs can vary significantly depending on your app’s scale and feature set. Below are a few realistic monthly examples to help frame expectations:
5,000 MAUs—Light to Moderate Usage
A typical hobby app or early-stage product with:
- 5,000 monthly active users (email/social login)
- Basic Firestore usage (e.g., 100K reads/day, 10K writes/day)
- No phone authentication or large file storage
Estimated monthly cost: $0–$30
Most usage stays within the free Spark tier, especially if you optimize Firestore reads. If you exceed free Firestore limits, expect light overages—primarily on reads and egress.
50,000 MAUs with SMS-based MFA
A B2C production app using:
- 50K MAUs on Firebase Authentication (email or social)
- Phone authentication for MFA (e.g. login and account recovery)
- Moderate Firestore and Cloud Function usage
Estimated monthly cost: $200–$400+
Breakdown:
-
Phone Authentication (SMS): In most apps, only 10–30% of users receive an SMS in a given month. At ~15,000 SMS/month × $0.01–$0.06/SMS, typical SMS costs range from $150–$900.
-
Firestore and Cloud Functions: Light to moderate usage beyond free limits (reads, writes, function invocations) adds another $50–$100/month, depending on usage patterns.
100K+ MAUs Using SAML/OIDC
A growing B2B app with:
- 100,000+ MAUs using Firebase Authentication (email/social)
- SAML/OIDC enabled via Identity Platform for select enterprise users
- Some SMS authentication in addition to Firestore usage
Estimated monthly cost: $500–$1,200+
Breakdown:
- Firebase Authentication MAUs:
Tiered pricing kicks in beyond 50,000 (~$0.0055–$0.0025/MAU).
- SAML/OIDC:
First 50 users free, then $0.015/MAU for enterprise logins.
- Phone Authentication:
Billed per SMS sent, typically $0.01–$0.06 depending on the recipient’s country.
- Firestore / Functions:
Scales with usage; common overages on reads, writes, and egress.
Hidden Costs to Watch Out For
Firebase’s free tier is generous, but certain features can quietly accumulate charges—especially as your app scales or expands globally. Here are some common areas where teams get caught off guard:
Phone Authentication
SMS authentication is not included in the free Spark plan and is billed per message on Blaze. Pricing varies significantly by recipient country—from $0.01 in the U.S. to $0.06 or more in regions like Europe or Africa.
Apps with a global user base or frequent SMS-based MFA can see costs rise quickly, especially if usage isn’t tightly controlled.
Advanced Authentication Features
Enabling OIDC or SAML login via Identity Platform adds powerful enterprise login options—but also introduces per-user billing.
The first 50 MAUs are free, but beyond that, pricing starts at $0.015/MAU. If you’re targeting B2B or offering SSO to enterprise clients, this cost kicks in early and scales with each onboarded organization.
Firestore and Cloud Function Scaling
Firestore reads and writes—and Cloud Function invocations—can grow rapidly with app activity. What starts as “well within the free tier” can turn into millions of operations per month as user engagement increases. Even modest increases in usage patterns (e.g., real-time sync, heavy querying, frequent function calls) can lead to unexpected charges.
Hosting and Bandwidth
Firebase Hosting offers 360 MB/day of free egress, but anything beyond that is billed at ~$0.15/GB. For apps with media files, client-side hydration, or high-traffic volumes, egress can quietly become one of your largest costs—especially if you serve international users.
While Firebase’s pricing model is clear, it’s not always predictable in practice. Small changes in user behavior—like choosing phone number login instead of email, or relying on Firestore for real-time chat—can significantly increase your monthly costs. Setting budget alerts, tracking usage regularly, and modeling worst-case traffic scenarios early on can help you avoid surprises and keep your infrastructure spend under control as you scale.
How Firebase Pricing Compares to Auth0 and Okta
Firebase stands out for its usage-based pricing and generous free tier, making it a popular choice for startups and mobile apps. But how does it stack up against competitors like Auth0 and Okta when it comes to pricing models and feature access?
- Free tier comparison:
Firebase offers 50,000 MAUs for free. Auth0’s free plan caps at 25,000 MAUs, with basic features and limited support. Okta does not offer a free tier for developers.
- Linear vs tiered pricing:
Firebase uses pay-as-you-go billing on Blaze. Auth0 and Okta use tiered plans, where unlocking basic enterprise features often requires a steep jump.
- Feature availability:
Firebase Authentication covers core use cases (email, social, phone), but does not provide enterprise features like RBAC, audit logs, or advanced MFA out of the box. These require Identity Platform or custom code. In contrast, Auth0 and Okta bundle many of these in their standard paid tiers.
If you’re building a consumer app or MVP, Firebase can offer better cost control—but larger teams may outgrow it faster than they expect.
Why Teams Choose SuperTokens Over Firebase
For growing teams frustrated with Firebase’s unpredictable costs or missing enterprise features, SuperTokens has become a go-to alternative. It offers the control of open-source authentication without the headache of piecing together multiple paid add-ons. Here’s why engineering and product teams are making the switch:
Open-Source Self-Hosted Authentication
SuperTokens gives teams the option to self-host for free, with no MAU limits or surprise usage-based charges. There’s no billing from SuperTokens tied to bandwidth or phone messages—just full access to all features under an open-source license.
Full Enterprise Features without Gated Upgrades
Unlike Firebase, SuperTokens offers MFA, RBAC, SSO, and session management as first-class features. These are available in the core product, without triggering extra per-MAU fees or requiring custom Identity Platform upgrades.
Clear Ownership of Data and Compliance
With Firebase, your user data lives inside Google Cloud. SuperTokens gives you full ownership of your authentication stack—making it easier to meet regional data laws, pass audits, and maintain compliance without vendor lock-in.
Easier Cost Forecasting
Firebase Authentication costs can spike based on how users log in or how often functions are triggered. SuperTokens avoids that by tying billing directly to MAUs—no need to monitor reads, writes, or bandwidth to stay within budget.
If Firebase’s invisible meters and upgrade traps are getting in the way, SuperTokens offers a clean, developer-first alternative—one that prioritizes transparency, ownership, and long-term scalability.
Real User Feedback
Firebase Authentication is widely praised for its simplicity and reliability. On Reddit, one dev shared:
“Firebase auth is insanely good and simple. They even have libraries with the UI for login that you can embed…”
Another user adds:
“One of the nice things about Firebase is it’s basically an “abstraction” for some GCP services…you can always branch out to other GCP services…”
On the SuperTokens side, feedback is equally positive. One reviewer said:
“It took me 1 day to implement and can now peacefully delete all my tabs. And I am loving it!”
Another user highlighted session security:
“SuperTokens really helped me in improving my session management and also prevented many session attacks.”
Together, these real-world insights underscore Firebase’s developer-friendly ease of use and scale, alongside SuperTokens’ fast setup and robust session control—reinforcing why each appeals to different but overlapping developer audiences.
How to Estimate Your Firebase Spend
Firebase’s pricing can be deceptively complex due to its usage-based billing. To avoid surprises, start with the Firebase Pricing Calculator and model your app across four key areas:
- Authentication:
Multiply your expected monthly active users (MAUs) by the Blaze tier’s per-login cost.
- Firestore and Functions:
Estimate document reads/writes and number of invocations—these costs scale quickly with active usage.
- SMS and Bandwidth:
Account for phone verification and media storage, which can add up fast under usage-based billing.
If your project requires enterprise features like SAML, OIDC, or RBAC, you’ll also need to factor in the Identity Platform add-on—which introduces its own per-MAU pricing. Being proactive with cost modeling early on can help teams avoid bill shock as they scale.
Best Practices to Control Costs
Firebase can scale quickly—and so can your bill. Here are a few practical ways to keep costs predictable:
- Avoid SMS-based authentication when possible:
Use email/password or OAuth providers, to cut down on phone verification charges.
- Reduce Firestore reads:
Denormalize data, cache intelligently, and batch queries to minimize document access.
- Set alerts for usage spikes:
Use GCP budget alerts to track spending across bandwidth, storage, and Cloud Functions.
- Clean up stale data:
Regularly archive or delete inactive users and old Firestore documents to save on storage and reads.
Smart engineering choices can reduce Firebase bills by hundreds per month—without sacrificing performance.
Conclusion and Final Comparison
Firebase delivers generous free usage and serverless convenience, making it ideal for small teams and fast-moving apps. But as your user base grows or enterprise needs emerge, costs can climb unpredictably—especially with SMS, SAML, and Firestore scaling.
For predictable pricing and full feature control, SuperTokens offers a compelling self-hosted alternative with no MAU limits and all features available out of the box.
Next steps: Use the Firebase calculator to model your actual usage, then compare it side-by-side with SuperTokens to find the best fit for your team.