Robin Moffatt shows how to use Single Message Transforms inside Kafka Connect to reshape messages as you send them downstream:
Single Message Transforms (SMT) is a functionality within Kafka Connect that enables the transformation … of single messages. Clever naming, right?! Anything that’s more complex, such as aggregating or joins streams of data should be done with Kafka Streams — but simple transformations can be done within Kafka Connect itself, without needing a single line of code.
SMTs are applied to messages as they flow through Kafka Connect; inbound it modifies the message before it hits Kafka, outbound and the message in Kafka remains untouched but the data landed downstream is modified.
There’s quite a bit you can do with this, so check it out.