Apache HBase is an open-source, distributed database designed to handle large amounts of structured data. It is built on top of the Hadoop ecosystem and provides real-time read and write access to data. HBase is modeled after Google's Bigtable and is suitable for applications that require high scalability and flexibility. HBase stores data in a column-oriented format, allowing for efficient storage and retrieval. It is designed to scale horizontally, meaning that as data grows, more servers can be added to accommodate the increase. This makes HBase a popular choice for big data applications and analytics.