Overview
Firebase is Google's backend-as-a-service for mobile and web apps. Its two databases are Cloud Firestore, a document database with collections, queries and realtime listeners, and the older Realtime Database, a single JSON tree synced to clients. Both are accessed straight from client SDKs for Apple platforms, Android, the web, Flutter and Unity, protected by security rules, with offline caching.
The free Spark plan needs no payment method. Firestore quotas are daily: 50,000 document reads, 20,000 writes and 20,000 deletes, with 1 GiB of storage. Firebase Authentication is included free up to 50,000 monthly active users, and Hosting, Cloud Messaging, Crashlytics and Analytics have free allowances or are free outright.
The Blaze plan keeps the Spark allowances and bills the rest at Google Cloud rates. Firestore charges per document read, write and delete (in us-central1, $0.03, $0.09 and $0.01 per 100,000) plus storage and egress. Queries are billed by documents returned and index entries scanned, so data modelling and listener design drive cost more than data size does.
Firestore is proprietary and runs only on Google Cloud, so moving away means rewriting data access. For relational needs, Firebase now also offers SQL Connect on Cloud SQL for PostgreSQL, with a three-month trial and then from about $9.37 a month.
Pricing and plans
Free tier · no card
Spark plan, no payment method: Firestore 1 GiB stored, 50,000 reads, 20,000 writes and 20,000 deletes per day, 10 GiB egress a month; Realtime Database 1 GB stored, 10 GB/month download, 100 connections; Authentication up to 50,000 MAU; Hosting 10 GB storage and 360 MB/day transfer
At the limit Stops at the limit Use of a product past its no-cost quota is shut off until the next cycle unless you move to the Blaze plan.
No backups| Plan | Price | What you get |
|---|---|---|
| Spark | Free | Daily Firestore quotas, 1 GB Realtime Database, 50,000 auth MAU, Hosting; no Cloud Functions |
| Blaze | Pay as you go | Spark quotas included, then Google Cloud rates; Firestore reads $0.03, writes $0.09, deletes $0.01 per 100,000 (us-central1) |
What it does
- Cloud Firestore
- Document database with realtime listeners, offline support, composite indexes and vector search; regional or multi-region locations.
- Realtime Database
- Low-latency JSON tree synced to clients, up to 200,000 simultaneous connections per database on Blaze.
- Firebase Authentication
- Email, phone, anonymous and social sign-in; with Identity Platform free up to 50,000 MAU and 50 SAML/OIDC MAU.
- Security rules
- Declarative rules let clients access the database directly without a custom API server.
- Backups and PITR
- Scheduled Firestore backups, point-in-time recovery, restore and clone, billed per GiB on Blaze.
- Platform services
- Hosting, App Hosting, Cloud Functions, Cloud Storage, Cloud Messaging, Crashlytics and Remote Config in the same project.
Strengths and limitations
Strengths
- Free plan with no payment method and daily-resetting quotas
- Client SDKs with realtime sync and offline support across mobile, web and Flutter
- Authentication, hosting, messaging and crash reporting in one console
- No servers to size; billing is per operation
- Wide choice of Google Cloud regions, including many in the EU
Limitations
- Proprietary NoSQL APIs create lock-in to Google Cloud
- Per-read billing can spike with chatty listeners or unindexed query patterns
- Backups, PITR and named databases have no free quota and need Blaze
- Database location cannot be changed after creation
- No database branching for preview environments
Who it suits
Good for
- Mobile and Flutter apps that need realtime sync and offline mode
- Prototypes that want auth and database with no server code
- Teams already on Google Cloud
Look elsewhere if
- Relational data with complex joins and reporting, where Postgres fits better
- Read-heavy apps with unpredictable traffic that need a flat, predictable bill
Pricing history
-
Remote Config fetches become billable
Effective 2026-09-01: on the Blaze plan, 100,000 fetches a day per project are free, then $0.06 per 10,000 requests. They were previously listed at no cost. Source ↗
-
App Hosting outgoing bandwidth priced
Effective 2025-08-01: App Hosting egress is free up to 10 GiB a month, then $0.20/GiB uncached and $0.15/GiB cached. Source ↗
Alternatives to Firebase
| Tool | From | Free option | Stages |
|---|---|---|---|
| Supabase Managed Postgres backend platform | $25/mo | Free tier | |
| MongoDB Atlas Managed document database | $8/mo | Free tier | |
| Crunchy Bridge Managed PostgreSQL on AWS, Azure and GCP | $9/mo | ||
| Convex Reactive backend and document database | $25/mo | Free tier | |
| Neon Serverless Postgres | Usage-based | Free tier | |
| Redis Cloud Managed Redis | $5/mo | Free tier |
Questions
Is Firebase free?
Yes. The Spark plan needs no payment method and includes daily Firestore quotas of 50,000 reads and 20,000 writes, 1 GiB storage and up to 50,000 auth MAU.
How much does Firestore cost after the free tier?
On Blaze in us-central1, $0.03 per 100,000 document reads, $0.09 per 100,000 writes and $0.01 per 100,000 deletes, plus storage and egress; rates vary by location.
Should I use Firestore or Realtime Database?
Firestore offers richer queries, indexes and multi-region locations; Realtime Database is a single JSON tree billed on storage and download rather than per operation.
Is Firebase Authentication free?
Authentication is free up to 50,000 monthly active users with Identity Platform, then billed at Google Cloud rates; phone sign-in is billed per SMS.
Can Firestore data stay in the EU?
Yes. Firestore offers the eur3 multi-region and many EU regions such as Frankfurt, Belgium and Paris.
Sources read for this page