Realm review
A capable object-oriented mobile database now discontinued after Atlas Device SDK end-of-life.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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 synchronization. Its platform coverage included iOS, Android, Windows, macOS, and Linux, while its mobile specifications included iOS, Android, and Xamarin. The product was aimed at developers building object-oriented mobile apps that needed local data access alongside cloud synchronization.
Its main technical strength was the combination of local persistence, reactive access, and synchronization in one mobile-oriented technology. SDKs and libraries covered Java, Objective-C, JavaScript, Swift, and Xamarin, supporting several common mobile development approaches. Realm Studio added a way to inspect Realm database files, which could help developers examine stored data during application work. MongoDB Atlas was the listed integration, giving the product a direct connection to MongoDB’s cloud ecosystem. MongoDB renamed Realm as MongoDB Atlas Device SDKs in 2023 and continued the project under the Apache 2.0 license.
The decisive limitation is lifecycle status. MongoDB announced that Atlas Device Sync and the Atlas Device SDKs reached end-of-life on September 30, 2025, so Realm should be considered discontinued for current software selection. It may remain relevant when maintaining an existing application that already depends on Realm data structures or SDKs, but it is not a suitable foundation for a new mobile database project that needs an active roadmap. Teams choosing a current platform should look beyond Realm, while teams managing legacy object-oriented mobile apps may still need to understand its persistence, synchronization, SDK, and inspection model.
Realm pros and cons
- 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
Realm fact sheet, pricing and score →
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