Backend-as-a-Service · Databases (Core)
Firebase vs MongoDB
Side by side
- Pricing model
- FirebaseUsage-based
- MongoDBUsage-based
- Starting price
- FirebaseUsage-based (Blaze)
- MongoDB$9/mo (Atlas Flex)
- Free tier
- FirebaseYes — Generous Spark free tier
- MongoDBYes — Atlas free tier (512MB shared cluster)
- Availability
- FirebaseGenerally available
- MongoDBGenerally available
- Last checked
- FirebaseOct 12, 2026
- MongoDBOct 12, 2026
| Fact | Firebase | MongoDB |
|---|---|---|
| Pricing model | Usage-based | Usage-based |
| Starting price | Usage-based (Blaze) | $9/mo (Atlas Flex) |
| Free tier | Yes — Generous Spark free tier | Yes — Atlas free tier (512MB shared cluster) |
| Availability | Generally available | Generally available |
| Last checked | Oct 12, 2026 | Oct 12, 2026 |
When each one fits
Choose Firebase when…
Mobile/web apps needing a quick backend
All-in-one BaaS with realtime sync
Realtime/collaborative features
Live data out of the box
Firebase strengths
Complete mobile/web backend
Realtime data sync
Fast to build with
Choose MongoDB when…
Apps with flexible/evolving schemas
Document model avoids rigid migrations
Rapid prototyping with JSON data
Natural fit for JS/TS object shapes
MongoDB strengths
Flexible document model
Easy horizontal scaling
Atlas managed + vector search
Trade-offs
Known weaknesses from each tool’s record. Sourced ones link to where they came from.
Firebase
Firebase ML service is being discontinued, forcing migration or loss of functionality.
Firebase Admin Dart SDK is experimental and not production-ready.
MongoDB
Weaker for complex relational queries
No source on file
Atlas costs can grow
No source on file