Apache Pulsar

Apache Pulsar is a distributed pub-sub messaging and streaming platform for moving event streams and queued messages at scale. Its flexible messaging model and client API serve applications that need topics, queues, or both from a single broker.

Pulsar scales horizontally to millions of topics while keeping strong ordering and consistency guarantees, backed by low-latency durable storage and transparent batching, partitioning, and geo-replication. Consumer cursor tracking, a built-in load balancer, and a REST admin API round it out, and native multi-tenancy adds per-tenant authentication, authorization, quotas, and optional hardware isolation.

Apache Pulsar is governed by the Apache Software Foundation under the Apache License 2.0. It is self-hosted, with a Helm chart, Docker images, language clients, and management tools across the surrounding ecosystem.