In Ressor, the Translator is responsible for transforming raw binary input to the entities consumed by services. More specifically, this is a layer between a Source and your service factory constructor/method.
You can find all default translators in a xyz.ressor.translator.Translators helper class.
You can always implement your own and provide it to Ressor while building the service.
Translators support chaining and prepending, so you can easily convert from one data representation to another.