Apache Pulsar is an open-source distributed pub-sub messaging system originally
created at Yahoo and now part of the Apache Software Foundation.

Read the docs GitHub

Key features

Pulsar Functions New

Easily deploy lightweight compute logic using developer-friendly APIs without needing to run your own stream processing engine

Proven in production

Pulsar has run in production at Yahoo scale for over 3 years, with millions of messages per second across millions of topics

Horizontally scalable

Seamlessly expand capacity to hundreds of nodes

Low latency with durability

Designed for low publish latency (< 5ms) at scale with strong durabilty guarantees


Designed for configurable replication between data centers across multiple geographic regions


Built from the ground up as a multi-tenant system. Supports Isolation, Authentication, Authorization and Quotas

Persistent storage

Persistent message storage based on Apache BookKeeper. Provides IO-level isolation between write and read operations

Client libraries

Flexible messaging models with high-level APIs for Java, C++ and Python


REST Admin API for provisioning, administration, tools and monitoring. Deploy on bare metal or Kubernetes.

Apache Pulsar is an effort undergoing incubation at The Apache Software Foundation (ASF) sponsored by the Apache Incubator PMC. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.

Apache Pulsar (incubating) is available under the Apache License, version 2.0.