H2 Database Engine vs ObjectBox
H2 Database Engine
h2database.com
ObjectBox
objectbox.ioSide by side
| Figure | H2 Database Engine | ObjectBox |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | Yes |
| Open source | — | — |
| Web | Yes | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| iOS | — | Yes |
| Android | — | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 2 |
| Spec score · Embedded Databases | 8.1 (#9) | 7.9 (#14) |
| Security | The security page warns that H2 is not designed for adversarial environments and advises against exposing an H2 server to untrusted connections. | ObjectBox Sync Server supports JWT authentication and can use TLS by supplying a certificate; its documentation describes no-authentication mode as insecure. |
| Support | The home page directs users to Stack Overflow and a Google Group for support. | The FAQ directs questions to documentation and Stack Overflow, and says professional support is offered to paying customers. |
Plans
In their own words
H2 Database Engine
H2 Database Engine is a free SQL database written in Java. It runs in embedded, server or mixed modes, with databases held on disk or in memory. H2 supports standard SQL and JDBC; server mode also accepts JDBC or ODBC over TCP/IP. A browser-based Console provides autocomplete. Listed database capabilities include transactions, multi-version concurrency and row-level locking, with JSON data support and high availability listed. Compatibility modes cover IBM DB2, Apache Derby, HSQLDB, MS SQL Server, MySQL, Oracle and PostgreSQL. Database files can use AES-128 encryption, while remote JDBC connections can use TLS. H2 is available for Linux, macOS and Windows, as an API, and for self-hosted or web deployment. It is dual licensed under MPL 2.0 or EPL 1.0, allowing integration into and distribution with commercial applications. The JAR is described as around 2.5 MB. The plan costs nothing.
ObjectBox
ObjectBox is an embedded, object-oriented NoSQL database for mobile applications and IoT devices. Its database provides native object APIs, relationships, reactive observers, ACID transactions and automatic schema migration. ObjectBox Sync can move data between devices and a backend or server, including for offline-first use cases. Listed language APIs include Java, Kotlin, Swift, Flutter/Dart, Go, Python and C/C++. The product supports vector search, with no embedding-column dimension limit stated in its FAQ. ObjectBox says it supports direct synchronization to MongoDB; connectors for other backend databases may require custom development. Its Sync Server can be self-hosted on POSIX systems and cloud providers, though ObjectBox does not currently provide cloud hosting. The core database plan is free; Sync pricing is quoted per project based on needs. The company describes its focus as mobile and IoT development, particularly decentralized systems with restricted devices and offline scenarios. Mesh Sync is available for Android Java/Kotlin and Flutter/Dart starting with version 6.0.0-beta, with APIs that may change before final release.