As others have mentioned you have lots of options: LMDB, LevelDB/RocksDB, BerkeleyDB. For what it's worth, I spent a long time looking for an embedded key-value

As others have mentioned you have lots of options: LMDB, LevelDB/RocksDB, BerkeleyDB. For what it's worth, I spent a long time looking for an embedded key-value store for my current native project since I didn't need the full complexity of SQL. In the end I chose... SQLite. All of these embedded NoSQL databases seem to be missing critical features. One such feature for my use case is database compaction. Last I checked, an LMDB database file can never shrink. Full compaction of LevelDB is slow and complicated (as I understand it essentially breaks the levels optimization which is the whole point of the thing.) SQLite meanwhile supports fast incremental vacuum, and it can be triggered manually or automatically. SQLite just has everything. Plus the reliability is unmatched. Even if you just need a single table that maps blob keys to blob values, I would still recommend SQLite over any NoSQL database today.