Document-based databases are a type of NoSQL database that store data in the form of documents, typically using formats like JSON or XML. Each document is a self-contained unit that can hold various types of data, including text, numbers, and arrays. This structure allows for flexible and dynamic data storage, making it easier to manage unstructured or semi-structured information. These databases are designed to handle large volumes of data and can scale horizontally, meaning they can distribute data across multiple servers. Popular examples of document-based databases include MongoDB and CouchDB, which are widely used for applications that require quick access to diverse data types.