What type of database is Amazon DynamoDB?

Amazon DynamoDB is a fully managed NoSQL database service that primarily stores information as key-value pairs, which makes it a key-value database. Each item in DynamoDB is composed of a primary key, which can be either a single attribute or a composite of two attributes, allowing for efficient retrieval.

This design enables quick lookups and scalable performance, particularly suitable for applications that require high availability and the ability to scale horizontally. Although DynamoDB can also store data in a document format using its support for attributes and nested structures, its core operation and primary classification align with that of a key-value database. The flexibility to support document storage does not reclassify it as a document database in the traditional sense; it remains fundamentally a key-value store at its core functionality.

Thus, the characterization of DynamoDB as a key-value database is accurate, as it excels in providing high-performance access patterns for applications that need to retrieve data using keys.