Kafka InitProducerId Response Wire Format v2 — Binary Protocol Layout

What is InitProducerId?

Every idempotent or transactional producer calls this before sending records to obtain a producer ID and epoch. The epoch prevents zombie producers: a restarted instance bumps the epoch, and late-arriving writes from the old instance are rejected with INVALID_PRODUCER_EPOCH.

Schema
{
  "ThrottleTimeMs": int32,
  "ErrorCode": int16,
  "ProducerId": int64,
  "ProducerEpoch": int16
}

Example
{
  "ThrottleTimeMs": 0,
  "ErrorCode": 0,
  "ProducerId": 0,
  "ProducerEpoch": 12
}