@U0GCYLN9M here’s one of the libs: https://github.com/FundingCircle/jackdaw

Depends on what you want to do, if it's only data transformation i'd pick kafka streams/jackdaw as its a solid library for that.

If you want to load/store data as well, and the data sources are not covered by the Kafka Connect, i'd consider onyx

There is not much active development done on Onyx, so you'll want to take that into account as well.