EJDB2 vs ObjectBox

EJDB2 is a free, MIT-licensed JSON database engine implemented as a C library for embedding in applications. It stores data in a single file, using the IOWOW persistent key/value storage engine. Its JQL query language supports filtering, data modification, collection joins, projections, sorting, indexes, and options to skip, limit, or count results; online backup is also listed. For network access, the standalone jbs server provides HTTP REST and WebSocket endpoints. The server supports TLS 1.2, can require an access token in the X-Access-Token HTTP header, and offers a write-ahead-log option for durability. EJDB2 provides a C11 API and lists macOS, iOS, Linux, Windows, and self-hosted availability. The repository links to language bindings and tags the project with C, Dart, Flutter, Java, Node.js, React Native, and Swift, but its changelog says only Java and Node.js bindings are maintained after a 2025 cleanup. The project README says its issues tracker is disabled and welcomes contributions and pull requests. The listed plan is EJDB2 at free.

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.