Yes, Firebase is free to start. Firebase's Spark plan comes with free usage limits and Firebase says no card is needed, so you can build with Authentication, Cloud Firestore, Analytics and more without upgrading. Some services, including Cloud Functions and Cloud Storage, need the Blaze plan.
The Spark plan is a good fit for prototypes, student projects and small apps. The two things to understand are the daily limits on Firestore and the list of services Spark doesn't include at all. Here's how it works.
What the Firebase Spark plan includes
Firebase's plans page lists these with free usage on Spark:
- A/B Testing, Analytics and App Distribution, listed as included.
- Authentication up to 50,000 monthly active users, with SAML and OIDC sign-in up to 50 monthly active users.
- Cloud Firestore with 1 GiB of stored data and 10 GiB of network egress a month.
- App Check, subject to limits that vary by attestation provider.
Cloud Firestore daily limits on Spark
| Firestore standard edition | Spark plan limit |
|---|---|
| Stored data | 1 GiB total |
| Document reads | 50,000 a day |
| Document writes | 20,000 a day |
| Document deletes | 20,000 a day |
| Network egress | 10 GiB a month |
Firebase says the free usage limits are enforced daily and refreshed at midnight. So if a busy day pushes you past 50,000 reads, the limit comes back the next day rather than at the end of the month.
What Spark doesn't include
This is the part that trips people up. Firebase's plans page marks several services as not applicable on Spark, which means you need the Blaze plan to use them at all:
- Cloud Storage, including uploads and downloads from storage buckets.
- Cloud Functions.
- App Hosting.
- Cloud Run, Cloud Build and Artifact Registry.
- Phone Authentication by SMS in all regions.
If a tutorial tells you to deploy a Cloud Function, that step needs Blaze. Firebase says Blaze still includes the Spark plan's free usage, so moving up doesn't remove your free allowance.
How to stay on the free plan
- Create your Firebase project on the Spark plan. There's no card to add.
- Use Authentication, Firestore and Analytics for your first version.
- Watch Firestore reads in the Firebase console, because they're usually the first daily limit you'll hit.
- Avoid features marked not applicable on Spark until you're ready to move to Blaze.
- Upgrade only the project that needs it when you're ready.
Hosting and Realtime Database on Spark
Two more services that people use on day one are included on Spark, with these limits from Firebase's plans page:
| Service | Spark plan limit |
|---|---|
| Hosting storage | 10 GB |
| Hosting data transfer | 360 MB a day |
| Hosting custom domain and SSL | Included |
| Realtime Database connections | 100 at once |
| Realtime Database storage | 1 GB |
| Realtime Database downloads | 10 GB a month |
| Remote Config fetches | 100,000 a day per project |
Firebase also lists Cloud Messaging and Crashlytics as included. So for a simple app with sign-in, a database, push notifications and a hosted web page, Spark covers the basics.
The Cloud SQL trial catch
Firebase's SQL Connect comes with a 3 month trial of Cloud SQL for PostgreSQL, limited to one per project. Firebase says that if you haven't moved the project to Blaze by the end of the trial, the instance is archived, and after a further 90 days it's deleted. If you try it, put a reminder in your calendar.
When to move from Spark to Blaze
- You need Cloud Functions, Cloud Storage or App Hosting.
- You're regularly going over 50,000 Firestore reads in a day.
- Your app needs phone sign-in by SMS.
- You want more than 100 Realtime Database connections at once.
Until one of those happens, Spark is enough, and Firebase says Blaze keeps the same free usage when you do move.
Is the Firebase free plan enough?
For a prototype, a hackathon app or a small internal tool, yes. Authentication for up to 50,000 monthly users is generous, and the daily Firestore reset means a spike doesn't lock you out for long. If you're comparing backends, my roundup of FlutterFlow alternatives covers app builders that sit on top of Firebase, and my list of free AI app builders helps if you'd rather not write the code yourself.
If you're building with an AI app builder or following a template, check which Firebase services it relies on before you start. An app that stores photos or files people upload needs Cloud Storage, and that means Blaze, even if everything else in the app fits comfortably on Spark.
My verdict: Firebase is free on the Spark plan, and it's a solid way to build and test without a card. Just check the list of services Spark leaves out before you plan your app, because Cloud Storage, Cloud Functions and App Hosting need Blaze.
Want AI doing the heavy lifting in your marketing?
I build the systems that handle the boring 80 percent, so you get your week back. Done properly, with the human kept in.
Frequently asked questions
Is Firebase free to use?
Yes. Firebase's Spark plan has free usage limits and doesn't need a card. Some services, such as Cloud Functions and Cloud Storage, need the Blaze plan.
What are the Firestore limits on the Firebase free plan?
Firebase lists 1 GiB of stored data, 50,000 document reads a day, 20,000 writes a day, 20,000 deletes a day and 10 GiB of egress a month.
When do Firebase free limits reset?
Firebase says its free usage limits are enforced daily and refreshed at midnight.
Can I use Cloud Functions on the Firebase free plan?
No. Firebase's plans page marks Cloud Functions as not applicable on Spark, so you need the Blaze plan.
Does Blaze still include the free usage?
Yes. Firebase says Blaze includes the Spark plan's free usage.
Is Firebase Hosting free?
Yes, on Spark. Firebase lists 10 GB of Hosting storage, 360 MB a day of data transfer and a custom domain with SSL.
Is Cloud Storage free on Firebase?
Not on Spark. Firebase's plans page marks Cloud Storage as not applicable on the Spark plan, so you need Blaze.
Does Firebase need a card to start?
No. Firebase says no card is needed for the Spark plan.
How many users can sign in free on Firebase?
Firebase lists Authentication for up to 50,000 monthly active users on Spark, and up to 50 for SAML and OIDC sign-in.
Is the Firebase Realtime Database free?
Yes, on Spark. Firebase lists 100 simultaneous connections, 1 GB stored and 10 GB of downloads a month.
