WaveDB is SQLite with a HTTP interface.
It is a ~6MB (~2MB UPX-compressed) self-contained, zero-dependency executable that bundles SQLite 3.35.5 (2021-04-19) with JSON1, RTREE, FTS5, GEOPOLY, STAT4, and SOUNDEX.
If you are already a fan of SQLite, WaveDB acts as a thin HTTP-server wrapper that lets you access your SQLite databases over a network.
WaveDB can be used as a lightweight, cross-platform, installation-free companion SQL database for Wave apps. The h2o-wave package includes non-blocking async functions to access WaveDB.
Database files managed by WaveDB are 100% interoperable with SQLite, which means you can manage them with the sqlite3 CLI, backup/restore/transfer them as usual, or use Litestream for replication.