@morti To add to this, this is essentially (if not just very similar) to nifi's Record API where Record processors require a RecordReader/Writer controller service where the schema for the incoming/outgoing files is defined. All these processors can get their schema from some registry, or have it configured hard-coded, or try to infer the schema, or simply rely on the schema that was given to the flowfile earlier in the flow.   I think it's worth looking into Records in nifi, they're designed specifically for well-defined data and use-cases similar to what your described  ... View more