HBase is an open-source, non-relational, distributed database modeled after Google's Bigtable and written in Java. It is designed to provide fast, random access to large volumes of structured data, making it ideal for real-time read/write access to big data. HBase runs on top of the Hadoop Distributed File System (HDFS) and integrates seamlessly with other Hadoop ecosystem components, such as Apache Hive and Apache Pig. Its scalability and fault-tolerance features make HBase a popular choice for applications requiring high throughput and low latency.