Kafka vs Pulsar: Which Streaming Platform?
Kafka is the dominant distributed event log with a huge ecosystem; Pulsar is a streaming platform with separated compute/storage and built-in multi-tenancy.
Kafka pairs brokers with log storage and has the largest streaming ecosystem (Connect, Streams, Schema Registry). Pulsar separates serving (brokers) from storage (BookKeeper), offering native multi-tenancy, geo-replication, tiered storage, and both streaming and queue semantics. Kafka wins on maturity and ecosystem; Pulsar offers architectural flexibility and built-in multi-tenancy.
| Kafka | Pulsar | |
|---|---|---|
| Architecture | Broker + log | Broker + BookKeeper |
| Multi-tenancy | Add-on | Native |
| Models | Streaming | Streaming + queue |
| Ecosystem | Largest | Growing |
| Best for | Mature streaming stacks | Multi-tenant, tiered storage |
Use case and ecosystem
Kafka is the safe default thanks to tooling, hiring pool, and managed offerings everywhere. Pulsar appeals when you need native multi-tenancy, unified streaming-and-queue semantics, or independent scaling of storage and compute. Kafka KRaft mode has also simplified its operational story.
In CI
Both run in containers for integration tests, though Pulsar has more moving parts (brokers plus BookKeeper). Wait for readiness before producing/consuming. Either fits managed runners, where faster runners shorten cluster startup and end-to-end tests.
The verdict
Maximum ecosystem, tooling, and hiring familiarity: Kafka. Native multi-tenancy, tiered storage, and unified streaming/queue semantics: Pulsar. Most teams default to Kafka and choose Pulsar when its multi-tenant, separated-storage architecture is a clear fit.