Realm Is Deprecated: Which Mobile Database to Use in 2026

If your app stores data in Realm, the company behind it has stepped back: MongoDB deprecated the Realm SDKs in September 2024 and removed Atlas Device Sync on September 30, 2025. The local database still runs and is still open source, but most old realm.io links now go nowhere, and several SDKs no longer get regular releases. For local storage in 2026, the safe default is SQLite through your platform's standard library. If you need sync, choose a sync engine first and a local store second.

This page replaces the Realm product pages, news posts and academy tutorials that older articles still link to. Dates come from MongoDB's own documentation. Versions come from the official package registries and were checked on October 17, 2026.

Disclosure: App369 is my studio, and I build mostly with Flutter and Firebase, both of which appear below. No vendor on this page paid for a mention.

What happened to Realm, and when

Two parts of Realm were affected differently:

• The on-device database carries on. MongoDB's notice says it "will continue to exist as an open source project", and MongoDB keeps community branches of the C++, Flutter, Kotlin, .NET, JavaScript and Swift SDKs with the sync code removed.
• Atlas Device Sync is gone, and with it App Services authentication, the Wire Protocol, and calling Atlas Functions directly from the SDK. Database triggers in Atlas are not affected. See MongoDB's App Services deprecation page for the full list.

How alive each Realm SDK is

"Open source" doesn't mean "maintained". This is the most recent release of each SDK on October 17, 2026:

If your platform's SDK has stopped releasing, the risk isn't that your app breaks tomorrow. It's that a future Xcode, Android Gradle Plugin or Flutter release breaks the build, and nobody ships a fix.

What the old addresses do today

Checked on October 17, 2026:

• realm.io redirects to MongoDB's deprecation notice.
• realm.io product pages, such as /products/realm-mobile-database/, return 404.
• news.realm.io and academy.realm.io, where the release announcements, tutorials and cheat sheets lived, no longer resolve. Old realm.io/news/... links redirect to academy.realm.io and fail there.

The Wayback Machine has copies of most of these pages if you need an old API detail.

The 2026 options compared

Versions were checked on the official registries on October 17, 2026. "Sync" means the product syncs data with a server or other devices itself; you can always build your own sync on top of a local store.

Local databases (no built-in sync)

The original Isar (last published in April 2023) and Hive (last published in June 2022) packages haven't had a release in years. Their community continuations, isar_community and hive_ce, are the ones getting updates.

Databases and engines with sync

MongoDB's own list of alternative sync providers also includes AWS AppSync, HiveMQ, Ably, Parse and Cedalo. If you also need a new backend, not just a new device database, my guide to backend options after Parse, Kinvey and Realm Sync covers Firebase, Supabase, Parse Server, Appwrite and PocketBase.

How to choose

1. You only used Realm to store data on the phone. Move to SQLite through your platform's standard tool: Room on Android, GRDB or SwiftData on iOS, Drift in Flutter, expo-sqlite or op-sqlite in React Native. SQLite will outlive every wrapper on this page.
2. You like Realm's object model and use Flutter. isar_community is the closest in feel. Check the package's activity before you commit, because community projects depend on a few maintainers.
3. You used Atlas Device Sync and your backend is MongoDB. Start with PowerSync or Ditto, the two with published migration guides. PowerSync's guide notes that Realm can run in parallel during the move.
4. Devices need to sync with each other without the internet (field work, retail, aviation). Ditto and Couchbase Lite both sync peer-to-peer.
5. You're starting a new app and want the least backend work. Firestore with offline persistence covers most apps that need to work on a train and catch up later. Test conflict handling with two devices editing the same record before you rely on it.
6. You can't move yet. Keep the Realm community build, pin your SDK version, and add a CI job that builds against the newest Xcode or Android tools, so you see breakage before your users do.

Migration checklist

1. Inventory every Realm model and query. Note relationships, embedded objects, lists and any live queries or change listeners your UI depends on. Live updates are often the hardest part to replace.
2. List everything Atlas did for you. Sync, App Services authentication, functions called from the app, permissions rules. Each one needs a new home.
3. Pick the target and prove it on one screen. Port the most complex screen first, on a real phone, with production-sized data.
4. Write a one-time importer. On first launch of the new version, read the old Realm file, write the data into the new store, and mark the import as done. Keep the old file until the import is confirmed.
5. Handle the unhappy paths. Low storage, a killed app mid-import, and a user who skipped several versions.
6. Test sync conflicts with two devices. Edit the same record offline on both, then reconnect. Decide what should win and check that it does.
7. Release in stages. TestFlight and Google Play internal testing first, then a staged rollout, and watch crash reports for import failures.
8. Remove Realm last. Drop the dependency only after the importer has run for most active users.

Need a hand?

If the migration is stuck on one bug, such as an import that loses records, a crash after the switch or a sync loop, the App Fix Ticket is a fixed-price option. The Diagnosis is $450 in 3 business days, with a fixed repair quote and the fee credited toward the fix. The Fix is $1,200 in 5 business days, with a pull request, a regression test and handover notes. It covers Flutter, Swift, Kotlin, React, Vue, Firebase and Node.js, and it doesn't cover rewrites. For a full migration, get in touch and I'll scope it.