Producer Acknowledgments Acks and Reliability Guarantees

In Apache Kafka, producer acknowledgments—configured via the acks parameter—determine how producers confirm that messages have been durably written to the cluster. Selecting the right acks level helps you balance throughput, latency, and data durability in your event-streaming applications.

What Are Acknowledgments (acks)?

When a producer sends a record to a Kafka broker, it can request an acknowledgment from the broker before considering the send successful. Acks define how many brokers must confirm receipt:

acks=0: No acknowledgment; the producer proceeds immediately.
acks=1: Leader broker acknowledgment only.
acks=all (or acks=-1): Confirmation from all in-sync replicas (ISRs).

Note

By default, Kafka producers use acks=1, offering a balance between performance and reliability.

Visual Overview

The image illustrates the concept of producer acknowledgments and reliability guarantees in Kafka, showing a producer sending a message to a broker with acknowledgment settings to limit data loss.

acks Configuration Options

acks Value	Description	Throughput	Data Guarantee	Typical Use Case
0	No broker acknowledgment	Highest	Possible message loss if broker crashes	Non-critical logging or metrics streams
1	Acknowledgment from leader only	High	Risk of loss if leader fails before replication	Standard event streams
all / -1	Acknowledgment from all in-sync replicas (ISRs)	Moderate to Low	Strongest durability as long as ≥1 ISR remains up	Financial transactions, audit logs

# Example: strong durability
acks=all

The image is a diagram illustrating producer acknowledgments and reliability guarantees in a data system, showing how producers interact with brokers and partitions to ensure limited data loss.

Choosing the Right Acks Level

Use the table below to select the appropriate acks configuration for your Kafka producer:

Objective	Recommended acks	Rationale
Maximum throughput	`acks=0`	No waits → minimal latency
Balanced performance	`acks=1`	Fast with leader confirmation
Maximum durability	`acks=all`	Guarantees replication to all ISRs

Warning

Using acks=all increases end-to-end latency. Ensure your cluster’s replication factor and in-sync replica settings are properly configured to avoid unintentional message rejections.

The image is a comparison chart of producer acknowledgment levels (acks=0, acks=1, acks=all) and their reliability guarantees, including use cases and potential message loss scenarios.

Best Practices

Always align your acks setting with your business requirements for reliability vs. performance.
Monitor ISR health to maintain durability when using acks=all.
Combine acks with other producer configs like retries and max.in.flight.requests.per.connection for end-to-end guarantees.

Links and References

Watch Video

Watch video content