What are acks in Kafka producer configuration?

acks controls how many broker acknowledgements the producer requires before considering a write successful. acks=0: fire-and-forget, no confirmation, maximum throughput, possible data loss. acks=1: leader confirms after its local write, followers replicate asynchronously — leader crash before replication means data loss. acks=all (or -1): leader waits for all in-sync replicas (ISR) to confirm — strongest durability. Together with min.insync.replicas, acks=all provides production-grade write durability.

Expected key concepts: acknowledgements, acks=0, acks=1, acks=all, durability, ISR, leader, fire-and-forget, data loss