With the recent deprecation of MongoDB Realm’s Device Sync feature, many developers need a reliable alternative for data synchronization in their applications. MongoDB announced that end-of-life for Atlas Data API, Custom HTTPS Endpoints, Atlas Device Sync (Realm Device Sync), Atlas Device SDKs (Realm), Atlas Data Lake (Preview) is only on the 30th of Sep 2025. And there are alternatives. For one, there is ObjectBox, a powerful and highly efficient Edge database with out-of-the-box Data Sync. We’re working on delivering all the functionalities and features you need and make ObjectBox a drop-in replacement for Mongo Device Sync asap. Please help us prioritize the most important things by filling out our questionnaire.
Now, let’s have a look at what ObjectBox can offer:
High-performance on-device database
ObjectBox is designed from the ground up for resource-efficiency and performance. It offers superfast database operations (CRUD: Create, Read, Update, Delete), often outperforming other database solutions, including Mongo Realm. However, we all know benchmarking is hard and it depends on the use case. So, check out our open-source benchmarks and make up your mind yourself.
Migration with native language APIs
While we do hope that our intuitive native-language APIs (Swift, Java/Kotlin, C/C++, Flutter / Dart, Python) and setup are straightforward and quick for anyone to adapt, we are also listening to you and willing to invest in making the migration easier. Reach out to us with your feedback.
Cross-Platform Support
Like Mongo Realm, ObjectBox supports any POSIX system, including Android, iOS, Linux, Windows, and MacOS. This cross-platform compatibility ensures that you can maintain a consistent data layer across all your applications.
Efficient Sync Solution
ObjectBox offers its own Data Sync (ObjectBox Sync), which provides reliable and efficient data syncing between devices and servers. This feature is the one you are looking for if you relied on Realm’s Device Sync capabilities. ObjectBox was built with Data Sync in mind. We do have a cluster-mode that has been heavily tested for efficiency and reliability by industrial customers. We can handle millions of concurrent connections while providing realtime synchronization.
Offline-First Approach
ObjectBox embraces an offline-first architecture, allowing your apps to work seamlessly without an internet connection. Data is stored locally and can be synced between devices when offline or synced back to, e.g., a cloud once a connection becomes available again, ensuring a smooth user experience in various network conditions.
Active Development and Support
Unlike MongoDB Realm Device Sync (Atlas Device Sync), which is now deprecated, ObjectBox is actively developed and supported. This means you’ll benefit from regular updates, bug fixes, and new features, ensuring your data management solution remains robust and up-to-date.
Vector Search
We recently extended our database to become the very first on-device vector database enabling on-device AI (e.g. RAG, genAI, more efficient AI) on Mobile, IoT, and other embedded devices, see the vector search docs here. While extending our offering to serve MongoDB Realm customers wanting to migrate is the priority now, we’ll be extending Data Sync to synchronize vector embeddings next year too.
Conclusion
As MongoDB Realm’s Device Sync reaches its end of life, now is the perfect time to explore alternatives that cannot only replace but potentially enhance your app’s data management capabilities. To learn more about how ObjectBox can help you transition from Realm, visit the ObjectBox docs or schedule a call.