Firestore vs Realm

Firestore8.9Visit Realm8.3Visit

Higher score Firestore #4 in Mobile Databases 8.9/10 Free plan Free plan✓ 0 of 1 features Visit Firestore

vs

Realm #8 in Mobile Databases 8.3/10 Open source ✓ 0 of 1 features Explore Realm

• Firestore fits best

  Cloud-backed document applications

• Realm fits best

  Legacy object-oriented mobile apps with cloud sync

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Side by side

Feature	Firestore 8.9/10 Visit ↗	Realm 8.3/10 Visit ↗
At a glance
Editor score	8.9	8.3
Ranking	#4 in Mobile Databases	#8 in Mobile Databases
Best for	Cloud-backed document applications	Legacy object-oriented mobile apps with cloud sync
Pricing model	Free plan + paid	Free
Starting price	—	Open source
Free plan	✓ (best)	Not checked yet
Free trial	—	—
Deployment	Cloud	Self-hosted, Mobile, Desktop
Platforms	Web, iOS, Android	iOS, Android, Windows, macOS, Linux
Support	Community, Docs	Community, Docs
Integrations	3 integrations	1 integrations
Features Firestore 0/1 · Realm 0/1
Offline mode	Not checked yet	Not checked yet
Specs
Data synchronization	Not checked yet	Not checked yet
Mobile platforms	Not checked yet	iOS, Android, Xamarin
Conflict resolution	Not checked yet	Not checked yet
SDK languages	Not checked yet	Java, Objective-C, JavaScript, Swift, Xamarin
Monthly sync limit	Not checked yet	Not checked yet
Our review
Pros	Offline persistence and real-time updates across mobile and web SDKs Security Rules integrate with Firebase Authentication Supports transactions, vector search, REST, and multiple access modes	Local persistence with reactive, object-oriented data access Device-to-cloud synchronization with MongoDB Atlas integration SDK coverage across iOS, Android, Xamarin and multiple languages
Cons	Usage-based billing varies by operations, storage, and network usage Cloud deployment does not provide a self-hosted deployment model Available access modes vary by the selected edition	Atlas Device Sync and Atlas Device SDKs reached end-of-life Not suitable for new projects requiring ongoing platform support Realm branding and documentation now point to legacy technology
Our verdict	Firestore is a managed, schemaless document database for mobile, web, and server applications. Its JSON-like collections and documents support nested maps, arrays, timestamps, binary data, geographic points, and vectors. The product is… Read the review →	Realm was an open-source mobile database and synchronization technology for reactive applications. It provided local mobile data persistence, object-oriented database access, reactive application data access, and device-to-cloud… Read the review →

Strengths and trade-offs

• Firestore — where it wins

  • Offline persistence and real-time updates across mobile and web SDKs
  • Security Rules integrate with Firebase Authentication
  • Supports transactions, vector search, REST, and multiple access modes

  Where it doesn't

  • Usage-based billing varies by operations, storage, and network usage
  • Cloud deployment does not provide a self-hosted deployment model
  • Available access modes vary by the selected edition

• Realm — where it wins

  • Local persistence with reactive, object-oriented data access
  • Device-to-cloud synchronization with MongoDB Atlas integration
  • SDK coverage across iOS, Android, Xamarin and multiple languages

  Where it doesn't

  • Atlas Device Sync and Atlas Device SDKs reached end-of-life
  • Not suitable for new projects requiring ongoing platform support
  • Realm branding and documentation now point to legacy technology

• Firestore8.9/10 · Free plan

  A cloud-managed document database with offline persistence, real-time updates, and vector search.

  Visit FirestoreFull verdict →
• Realm8.3/10 · Open source

  A capable object-oriented mobile database now discontinued after Atlas Device SDK end-of-life.

  Explore RealmFull verdict →