Conduit Beta – Matrix chat server 5 years ago
Conduit was built around sled in the past. It has been depreciated in favor of sqlite as sled was using too much memory. (and sqlite is used as a key-value storage)
As there is now an interface allowing to add several storage backend, more backends could be added later (for instance a real key-value storage rather than a RDBMS used as a KV-store)
(according to the article)