ObjectBox

ObjectBox is a local, object-oriented database for mobile and IoT software that needs dependable device-side data. It suits developers building offline-first or decentralized systems, especially when they want to run synchronization infrastructure themselves. The main decision is whether its capable embedded core and 1 GB database ceiling fit your application before committing to separately quoted Sync.

Overview

ObjectBox uses a document model and an API query interface, storing application data inside the device rather than behind a separate database server. That architecture is a strong match for restricted devices and applications that must remain useful during connectivity gaps. The maximum database size is 1 GB, however, which rules it out for local datasets expected to grow beyond that limit.

ObjectBox Sync can move data between devices and a backend or server, including offline-first deployments. The Sync Server runs on POSIX systems and cloud providers, but ObjectBox does not provide cloud hosting. Self-hosting gives teams deployment control, while also making server operation and security their responsibility.

Key features

Embedded database

Native object APIs, relationships between objects, ACID transactions, reactive observers and automatic schema migration cover substantial application data work without forcing developers into a server-centric design. Vector search is supported, with no limit on embedding-column dimensions, making the database relevant to applications that store and search embeddings as well as ordinary records.

Synchronization and integrations

Sync connects device data with another device or a backend and is designed for intermittent connectivity. Direct synchronization to MongoDB is supported; other backend database connections may require custom connectors. Mesh Sync is currently limited to Android Java/Kotlin and Flutter/Dart from version 6.0.0-beta, and its APIs may change before release, so it is not a stable cross-platform foundation yet.

Languages and security

APIs are available for Java, Kotlin, Swift, Flutter/Dart, Go, Python and C/C++, covering the main mobile stacks and several server or embedded environments. Sync Server supports JWT authentication and TLS when a certificate is supplied. Its documented no-authentication mode is insecure and should not be treated as a production shortcut. ObjectBox states that it is ISO-certified, while professional support is reserved for paying customers; other users are directed to documentation and Stack Overflow.

Pricing

Plan	Price	What it includes
ObjectBox Database	free	No cost; core database and fundamental capabilities
ObjectBox Sync	Custom pricing	Per-project quote. Pricing varies by users, devices, sync instances, business model, support and additional needs.

The free database is the sensible starting point for individual developers and teams that only need local storage, and there is no charge for its core capabilities. It does not include a predictable price for connected deployments: Sync is quoted per project, so budgets depend on scale and commercial requirements. A free trial is offered, but no duration is stated. Teams needing hosted infrastructure should also budget for their own cloud provider, since ObjectBox supplies no cloud hosting.

Platforms

ObjectBox supports Android, iOS, Linux, Windows, macOS, Raspberry Pi and POSIX systems. Its language coverage spans Java, Kotlin, Swift, Flutter/Dart, Go, Python and C/C++. That breadth is useful for products sharing a data approach across mobile, desktop, gateway and embedded targets, while Mesh Sync's current Android and Flutter beta scope is considerably narrower.

Who it's for

Choose ObjectBox for mobile and IoT applications that keep important state on devices, need transactions and schema evolution, and may synchronize after going offline. It is particularly suitable for decentralized systems of constrained devices and for teams comfortable operating a self-hosted Sync Server. It is a weaker fit for applications requiring local databases larger than 1 GB, turnkey managed synchronization, or a mature Mesh Sync API across every supported platform.

Pros and cons

Pros

• Free core database removes licensing cost for local-only applications.
• Object relationships, ACID transactions, observers and automatic migration provide a substantial embedded feature set.
• Vector search has no stated embedding-column dimension limit.
• Broad language and platform coverage supports mixed mobile and embedded estates.
• Self-hostable Sync Server and JWT/TLS options give teams control over deployment and authentication.

Cons

• The 1 GB maximum database size can constrain data-heavy devices.
• Sync has custom, project-based pricing rather than a published plan.
• No ObjectBox cloud hosting means customers operate the Sync infrastructure themselves.
• Non-MongoDB backend integrations may need custom development.
• Mesh Sync is still a beta, currently restricted to Android Java/Kotlin and Flutter/Dart.

Alternatives

For a wider directory of choices, see Mobile Databases and Embedded Databases.

• Espresso is a free Android UI-testing tool, so choose it for single-target Android testing rather than database storage.
• Hive is a free-forever option with 1,000 AI credits per month, 200 MB storage and up to 10 workspace members; choose it when those workspace-style limits fit better.
• RxDB offers a free core with replication and realtime sync; choose it when that web-inclusive replication model is preferable.
• Ditto has a free tier with 10 cloud device connections, 2 GB storage and 5 GB transfer, making it an alternative for a defined managed-cloud allowance.
• Realm is a free open-source database now associated with MongoDB Atlas Device SDKs; choose it when that ecosystem is the priority.
• Sparksee offers a free academic licence for eligible institutions.
• SQLDelight is a free open-source Kotlin SQL code-generation library for teams wanting SQL-oriented development.
• WCDB is a free open-source mobile database framework.

Verdict

ObjectBox is a strong recommendation for mobile and IoT developers who need a capable, free embedded database and can operate their own synchronization server. Its object APIs, offline orientation and broad platform support are compelling. Look elsewhere if a 1 GB local ceiling, custom Sync pricing, self-hosting duties or Mesh Sync's beta status conflicts with your product requirements.