Apache Pulsar is a cutting-edge, distributed platform for messaging and streaming that was initially developed at Yahoo! and has since become a prominent project under the Apache Software Foundation. It boasts straightforward deployment, a lightweight computing process, and APIs that are user-friendly, eliminating the necessity of managing your own stream processing engine. For over five years, it has been utilized in Yahoo!'s production environment, handling millions of messages each second across a vast array of topics. Designed from the outset to function as a multi-tenant system, it offers features like isolation, authentication, authorization, and quotas to ensure secure operations. Additionally, Pulsar provides configurable data replication across various geographic regions, ensuring data resilience. Its message storage relies on Apache BookKeeper, facilitating robust performance, while maintaining IO-level separation between read and write operations. Furthermore, a RESTful admin API is available for effective provisioning, administration, and monitoring tasks, enhancing operational efficiency. This combination of features makes Apache Pulsar an invaluable tool for organizations seeking scalable and reliable messaging solutions.