NATS vs Kafka
The lightweight message bus vs the enterprise event platform. Both move messages. They have very different opinions about how.
NATS
For 90% of messaging needs, NATS is simpler, faster to set up, and easier to operate. Kafka is for when you need guaranteed ordering, replay, and enterprise-scale event streaming. Most teams reach for Kafka when NATS would be more than enough.
Simplicity vs Power
NATS is a single binary. Download, run, connect. Pub/sub, request/reply, queue groups — all built in. JetStream adds persistence and exactly-once delivery.
Kafka requires ZooKeeper (or KRaft), brokers, topic configuration, partition planning, consumer group management. It's an entire infrastructure project.
When Kafka Wins
Event sourcing. Log compaction. Multi-datacenter replication. Consumer replay from any offset. These are things Kafka was built for and does exceptionally well.
If you need to replay every event from the last 30 days, process millions of events per second, or build a system where the event log IS the source of truth — Kafka is the right choice.
The Operations Tax
Kafka clusters require care. Partition rebalancing, broker failures, topic configuration, monitoring lag — you need a dedicated team or a managed service (Confluent, AWS MSK).
NATS runs on a Raspberry Pi. A 3-node cluster handles most workloads. Operations overhead is minimal.
Quick Comparison
| Factor | NATS | Kafka |
|---|---|---|
| Setup Complexity | Single binary | Multi-component |
| Latency | Sub-millisecond | Low (but higher) |
| Persistence | JetStream | Native (log-based) |
| Event Replay | Limited | Full offset replay |
| Operations Burden | Minimal | Significant |
| Throughput | High | Very high |
| Exactly-Once | JetStream | Yes (with config) |
The Verdict
Use NATS if: You need pub/sub, request/reply, or lightweight messaging without an infrastructure project. Microservices, IoT, edge computing.
Use Kafka if: You need event sourcing, log compaction, or process millions of events/second with replay capability.
Consider: RabbitMQ is the middle ground — more features than NATS, simpler than Kafka. Good for traditional task queues.
For 90% of messaging needs, NATS is simpler, faster to set up, and easier to operate. Kafka is for when you need guaranteed ordering, replay, and enterprise-scale event streaming. Most teams reach for Kafka when NATS would be more than enough.
Related Comparisons
Disagree? nice@nicepick.dev