MongoDB is a popular open-source NoSQL database designed for handling large volumes of unstructured or semi-structured data. Unlike traditional relational databases that store data in tables with rows and columns, MongoDB uses a flexible, document-oriented model. Data is stored in JSON-like documents (called BSON—Binary JSON), which allows for nested fields and varying structures across documents in the same collection.

This flexibility makes MongoDB ideal for applications that require rapid development, scalability, and the ability to handle diverse data types. It supports powerful querying, indexing, aggregation, and real-time analytics. MongoDB is also horizontally scalable through a process called sharding, which distributes data across multiple servers to handle large-scale deployments.

Developers appreciate MongoDB for its ease of use, dynamic schemas, and compatibility with modern programming languages. It’s commonly used in web applications, content management systems, IoT, and big data platforms. MongoDB also offers a cloud-based service called MongoDB Atlas, which simplifies deployment, scaling, and management.