Amazon DocumentDB
Developer Guide

What is a Document Database?

Some developers don't think of their data model in terms of normalized rows and columns. Typically, in the application tier, data is represented as a JSON document because it is more intuitive for developers to think of their data model as a document.

The popularity of document databases has grown because they let you persist data in a database by using the same document model format that you use in your application code. Document databases provide powerful and intuitive APIs for flexible and agile development.