ObjectBox

ObjectBox is an embedded NoSQL database with a separate product for synchronizing device data to other devices or a server. It is best suited to mobile and IoT teams building for offline use, while projects that need more than 1 GB of local database capacity or managed cloud hosting should look elsewhere. The core database costs nothing; Sync is priced by project.

Overview

ObjectBox keeps data in an embedded database rather than requiring a separate database server, and exposes it through object-oriented APIs. Its document model and API-based queries suit applications that want to work with device-local data directly. The 1 GB maximum database size is a material constraint: it can suit compact device datasets, but is a poor fit for installations expected to accumulate larger local stores.

Sync adds data exchange among devices and a backend or server, including for offline-first applications. That extends the database beyond a single device, but also means the sync deployment and its cost need separate consideration.

Key features

Local data and developer APIs

ObjectBox combines native object APIs and object relationships with ACID transactions, reactive observers and automatic schema migration. Together, these reduce the gap between application objects and stored data while covering transactional updates and schema changes. The database also supports vector search without a stated limit on embedding-column dimensions, a useful capability for applications that store and search embeddings.

Synchronization and deployment

ObjectBox Sync can synchronize data across devices and to a backend or server. Teams can run its server on POSIX systems and cloud providers, but must arrange hosting themselves; ObjectBox does not provide cloud hosting. Sync Server supports JWT authentication and TLS when supplied with a certificate. Its no-authentication mode is described as insecure, so it is not an appropriate deployment choice for protected data.

Direct synchronization to MongoDB is supported. Connecting other backend databases may require custom-built connectors, which can add work for teams whose systems do not use MongoDB.

Languages and maturity

APIs are available for Java, Kotlin, Swift, Flutter/Dart, Go, Python and C/C++, covering a broad range of mobile and application development stacks. Mesh Sync is a narrower, newer option: it is available for Android Java/Kotlin and Flutter/Dart starting with version 6.0.0-beta, and its APIs may change before final release. Teams needing stable interfaces should account for that beta status.

Pricing

ObjectBox Database is free: the free plan includes the core database and its fundamental capabilities. This makes it possible to use the embedded database without a license charge, but the 1 GB database ceiling still applies.

ObjectBox Sync has custom pricing, quoted per project. The quote varies with users, devices, sync instances, business model, support and additional needs. That can accommodate different deployments, but it prevents a straightforward per-seat or fixed-cost comparison before project requirements are defined. A free trial is available, though no trial length is stated.

Platforms

ObjectBox supports Android, iOS, Linux, Windows, macOS, Raspberry Pi and POSIX systems. That breadth suits software spanning phones, desktops and embedded devices, while the particular Mesh Sync platform support remains limited to Android Java/Kotlin and Flutter/Dart in beta.

Who it's for

ObjectBox is strongest for mobile and IoT developers building decentralized systems on devices with intermittent connectivity. Its embedded object database can keep application data local, while Sync provides a route to exchange it with other devices or a server. It is less compelling for teams seeking a managed synchronization cloud, a database larger than 1 GB, or ready-made connectors to backend databases beyond MongoDB.

The company is based in Germany and states that it is ISO-certified. The FAQ directs questions to documentation and Stack Overflow, with professional support offered to paying customers; teams relying on that support should include it in their Sync project requirements.

Pros and cons

Pros: The core database is free, with object relationships, transactions, reactive observers and schema migration included.

Pros: Sync supports offline-first device-to-server and device-to-device use cases, and the server can be self-hosted.

Pros: Broad language APIs and vector search make it relevant to more than basic local storage.

Cons: The 1 GB maximum database size rules it out for larger local datasets.

Cons: Sync requires a project-specific quote, and customers must provide their own hosting.

Cons: MongoDB is the directly supported backend connector; other database integrations may need custom work.

Cons: Mesh Sync is still beta and currently limited to specified Android and Flutter/Dart APIs.

Alternatives

For other embedded options, browse Embedded Databases or Mobile Databases. Choose SQLite instead when a free embedded SQL database engine with no separate server process is the priority. RxDB is another free-core option, with replication and realtime sync in its free plan. For an open-source Go library and command-line utility, consider bbolt; RocksDB is an open-source C++ library with GPLv2 or Apache 2.0 licensing.

Chroma offers an Apache 2.0-licensed codebase that also powers its cloud product. LadybugDB is available under the MIT license. PouchDB is a free and open-source alternative, while Qdrant offers a free cloud tier alongside its database.

Verdict

Choose ObjectBox for mobile or IoT software that needs a capable embedded object database and offline-first synchronization under your own deployment control. Its free core and broad APIs are persuasive, but the 1 GB ceiling, self-managed hosting and project-priced Sync make it a poor match for large local stores or teams seeking predictable costs and managed infrastructure.