MongoDB is a popular NoSQL database that is designed to handle unstructured data. It is a document-oriented database that stores data in JSON-like documents with dynamic schemas. MongoDB is known for its scalability, flexibility, and high performance. It is widely used in modern web applications, mobile apps, and IoT devices. MongoDB supports a wide range of programming languages and platforms, making it easy to integrate with existing systems. It also offers features like automatic sharding, replication, and indexing, which help to ensure high availability and data consistency. Overall, MongoDB is a powerful and versatile database that is well-suited for modern data-driven applications.