How are records converted to and from bytes in Kafka clients and in Kafka Connect?

Kafka clients convert objects to bytes with a Serializer (the producer's key.serializer and value.serializer settings) and back with a Deserializer on the consumer; the Serializer interface converts data into a byte array. The format itself (for example JSON or Avro) is a choice made in the serializer, so producers and consumers have to agree on it. In Kafka Connect, the key.converter and value.converter settings convert between Connect's data format and the serialized form written to Kafka; because this is independent of the connectors, any connector can work with any serialization format. A schema registry, a service that stores schemas so that messages need not carry them, is not described in Apache Kafka's documentation, so its compatibility rules and schema IDs should be taken from the documentation of the registry product you use.

Expected key concepts: Serializer, Deserializer, key.serializer, value.serializer, byte array, converter, key.converter, value.converter, JSON, Avro, schema registry