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Realm

realm.github.io

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Spec score 7.7 #18 of 26 in Mobile Databases

What it is

Realm is an object database for local data persistence in mobile and edge applications. It runs directly on phones, tablets, and wearables, and presents data as objects that developers can query in code without an ORM. The database supports relationships, generics, and vectorization. Its documentation describes apps continuing to work 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, as well as 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. Former Device Sync connected data across users, devices, and a backend in real time, but MongoDB announced deprecation of Device Sync and Realm SDKs in September 2024. Realm is free and open source under Apache License 2.0.

Spec sheet

Product
Realm is an object database designed to run directly on phones, tablets, and wearables.Read 4 Oct 2026 · github.com
Integrations
Realm's former Device Sync connected data across users, devices, and a backend in real time.Read 4 Oct 2026 · github.com
Security
Realm Swift says data can be encrypted in flight and at rest.Read 4 Oct 2026 · github.com
Support
The Realm documentation directs users to its forums, Stack Overflow, and GitHub issues for help.Read 4 Oct 2026 · realm.netlify.app
License
MongoDB said it would offer the renamed Atlas Device SDKs as a free open-source project under Apache License 2.0.Read 4 Oct 2026 · mongodb.com
Maker
MongoDB acquired Realm and its technology in 2019 and renamed it MongoDB Atlas Device SDKs in 2023.Read 4 Oct 2026 · mongodb.com
Data model
Realm exposes data as objects that can be queried in code without an ORM.Read 4 Oct 2026 · github.com
Database features
The database supports relationships, generics, and vectorization.Read 4 Oct 2026 · github.com
Deprecation
The Realm JavaScript repository says MongoDB announced deprecation of Atlas Device Sync and Realm SDKs in September 2024.Read 4 Oct 2026 · github.com
Developer tool
Realm Studio can open and edit local and synced Realms and administer Realm Object Server instances.Read 4 Oct 2026 · realm.netlify.app
Offline use
The Realm Platform documentation says apps can work through weak signal, offline, or outage scenarios.Read 4 Oct 2026 · realm.netlify.app
SDKs
The official documentation lists Java, Swift, Objective-C, JavaScript, and .NET SDKs.Read 4 Oct 2026 · realm.netlify.app
Supported platforms
The JavaScript implementation supports React Native on iOS and Android, plus Node.js and Electron on Windows, macOS, and Linux.Read 4 Oct 2026 · github.com
Use case
Realm provides local data persistence for mobile and edge applications.Read 4 Oct 2026 · github.com

Plans and prices

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

Every Realm plan and price →

Strong points and limits

Strong points

  • Objects can be queried in code without an ORM.
  • Supports relationships, generics, and vectorization.
  • Documentation describes operation through offline periods and outages.
  • Realm Swift supports encryption in transit and at rest.

Limits

  • MongoDB announced deprecation of Device Sync and Realm SDKs.
  • Former Device Sync is deprecated.

Who it suits

Realm suits developers building mobile or edge applications that need local object-based data persistence. Its listed SDKs and platform support cover several mobile, desktop, and server environments.

Verdict

Realm offers local object persistence with several SDKs and data features. Developers should account for MongoDB’s announced deprecation of Device Sync and Realm SDKs.

Where Specifiction places it

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