Kafka

Kafka is the backbone of event-driven architecture at scale — a distributed streaming platform that handles millions of messages per second with durable, replayable event logs. If your system needs to process events in real-time and you can't afford to lose a single one, Kafka is the industry standard.

Skip this if you're a solo founder building an MVP. Kafka is enterprise infrastructure that requires ZooKeeper (or KRaft), brokers, and ops expertise. RabbitMQ is simpler for traditional message queuing at 50-100K messages/second. NATS is lighter and faster for microservice pub/sub. Redis Streams works for small-scale event streaming.

The catch: Kafka is operationally heavy. Running it yourself means managing brokers, partitions, consumer groups, and storage. Confluent Cloud removes the ops burden but costs real money. And Kafka's learning curve is steep — topics, partitions, offsets, and consumer group rebalancing will take weeks to grok. For most indie projects, you don't need Kafka. You need a simple queue.