ObjectBox C / C++ Database

Create super-fast C and C++ applications with the embedded database and sync engine. Get started here with these two pages:

Alternatively, you can also dive into some examples on GitHub right away.

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Latest Versions (Changelogs)​

5.3.0 (2026-03-23)​

• Change log level at runtime, i.e. obx_log_level_set()/obx_log_level_get()
• New log level "trace" for most internal details
• Log level "verbose" can now be enabled (debug log builds only)
• Breaking: OBXLogLevel enum values changed; recompile with new header if you used these (previously 10/20/30/40/50 for Verbose..Error, now 0-10 matching the runtime log level).
• Admin: Status tab "Count and Sizes" now only counts all objects on click to preserve resources
• Admin: Status tab "Count and Sizes" now has a sum row at the bottom
• Admin: Status tab "System and Info" now shows additional information
  • Process memory / RSS
  • Database size and free disk size
  • CPU counts and loads

Sync​

• Conflict resolution via sync clock and sync precedence (allows last win with custom conflict resolution)
• Fix bad Sync client state after multiple full sync messages were interrupted
• Fix adding indexes to Sync types

5.2.0 (2026-03-06)​

• Admin: new "Counts and Sizes" view (via Status page) to give an overview over all types their object counts and sizes
• Admin: refresh button for the data view
• Admin: fix reload via browser to stay on the page
• Admin: schema view to display flags as text
• (Minor) performance improvements of HNSW vector search on Linux ARM targets

Sync​

• Sync protocol version 10
• Update client sync filters variables when online
• Clients report errors to the server
• Add OBXSyncFlags_SkipInvalidTxOps

5.1.0 (2026-01-19)​

• Fix for deleting transactions in non-owner threads with open relation cursors
• Admin: the Schema view now shows if external name of types and properties if configured
• Admin: the Schema view now shows the type as text (e.g. "String") instead of the internal type ID
• Internal updates

Sync​

• New Sync protocol V8: using new clients also require a server update
• Remove-operations with object content for Sync filters (optional setting; sync flag)
• Introduce options based Sync client creation (new C API)
• Add DebugLogTxLogs sync flag to log TX log processing on the client side
• Add SkipInvalidTxOps sync flag to skip invalid operations in a TX log on the client side; errors are logged and the TX is only partially applied.
• Remove superfluous sync listener triggers when sync filters "report updates" (SKIP_TX)
• Sync clients compress earlier: reduces disk storage for outgoing data
• Reworked SSL certificates for Apple platforms
• Removed support for older Sync protocol versions before 2024-09; protocol V5+ is now required

5.0.0 (2025-11-27)​

User-Specific Data Sync​

• Sync filters: define server-side filter expression to sync individual data for each sync user. This is also known as "user-specific data sync" and requires Sync clients version 5.0.
• Client variables: clients may define key/value pairs that can be used in sync filters

New supported platform: Windows ARM64​

• Besides x86 and x64, ObjectBox for Windows now also supports ARM64

Sync​

• Sync clients may now provide certificate locations for SSL (TLS) connections

Fixes​

• Fixed clearing 1:N backlinks for IDs larger than 32-bit (setting backlink ID to 0 on the "1" side)
• In-memory with WAL file: improved error handling
• Safeguard against undefined behavior by panicking in rare illegal usage patterns that are not recoverable. I.e. deleting a (write) transaction in a non-owner thread cannot be safely handled in any other way.
• Various small improvements and updates under the hood.

Examples​

• Make each example self-contained, you can e.g. copy an example's directory as a starting point for your own app
• Add a convenient build.sh script to each example that works the same way across examples, e.g. ./build.sh run to build and run the example in one step
• Make sources more readable (refactorings, added additional comments)
• The Task sync example moved to ObjectBox Sync Examples

Earlier Versions​

Changelogs for versions before 5.0 are now in Earlier Versions.

ObjectBox Generator​

Check the ObjectBox Generator releases for details.