<!here> Per popular request, we’ve put together a guide on how to write your own transformers! If you’ve got any custom ownerships, tags, or want to modify any metadata before it’s ingested, then this is the guide for you. Please see here for the updated transformer docs and tutorial. We’ve also posted the configs and scripts used in the tutorial here.

We use them all the time at Klarna. It's really handy to combine data from multiple sources which just update different aspects. while keeping the code isolated and clean.