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No. 6 of 27 ·Mobile Databases

Realm

Windows · Mac · Linux · Android · iPhone · Self-hosted

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Freedom report

Three barsScore 6.7

  • Free tierA free tier is on its own pricing page
  • Open codeNo open-source code on record
  • Runs widely5 of 6 device platforms
  • DocumentedPlans, terms and facts published

Realm is a free, open-source object database for local data persistence in mobile and edge applications. It runs directly on phones, tablets, and wearables, and lets developers query stored objects in code without an ORM. The database supports relationships, generics, and vectorization. Realm documentation describes apps continuing to operate through weak signal, offline periods, or outages. Listed SDKs include Java, Swift, Objective-C, JavaScript, and .NET. The JavaScript implementation supports React Native on iOS and Android, and Node.js and Electron on Windows, macOS, and Linux. Realm Swift supports encryption in transit and at rest. Realm Studio can open and edit local and synced Realms and administer Realm Object Server instances. MongoDB acquired Realm in 2019 and renamed it MongoDB Atlas Device SDKs in 2023. MongoDB announced deprecation of Atlas Device Sync and Realm SDKs in September 2024; Device Sync had connected data across users, devices, and a backend in real time. Realm Database is free under Apache License 2.0.

Who it is for

Realm suits developers building mobile or edge applications that need local data persistence and object-based queries. Its SDKs and platform support cover several programming languages and environments.

What is good

  • Free and open source under Apache License 2.0
  • Objects can be queried without an ORM
  • Supports relationships, generics, and vectorization
  • Realm Swift supports encryption at rest and in flight
  • Realm Studio edits local and synced Realms

What to know first

  • MongoDB announced SDK and Device Sync deprecation in September 2024
  • Documentation points to forums, Stack Overflow, and GitHub issues for support

Verdict

Realm offers local object persistence and SDKs across several languages and platforms. Its announced deprecation of the SDKs and Device Sync is important for developers assessing ongoing use.

Realm plans and pricing

All plans
Realm Database (open source) Free Free and open source under Apache License 2.0 mongodb.com · 4 Oct 2026

Compared on mobile databases

Mobile platforms
iOS, Android, Xamarin
SDK languages
Java, Objective-C, JavaScript, Swift, Xamarin

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