Question: Is DynamoDB based on MongoDB?

Answer

No. DynamoDB is an AWS database with its own API, not a MongoDB-compatible service. AWS built it in-house and launched it on January 18, 2012. Its design draws on lessons from Dynamo, the internal key-value store Amazon described in a 2007 research paper, but DynamoDB is a separate system despite the similar name. MongoDB is an independent document database developed by MongoDB, Inc.

How they differ in practice:

• API. DynamoDB is an HTTPS API (GetItem, Query, UpdateItem and so on) plus PartiQL, a SQL-compatible query language. MongoDB has its own query language, including find and the aggregation pipeline, and its own drivers.
• Data model. Both store JSON-like documents. DynamoDB is built around the primary key: efficient reads go through the table's key or a secondary index. MongoDB lets you query and index almost any field ad hoc.
• Operations. DynamoDB is serverless and runs only on AWS. MongoDB runs anywhere: self-hosted, or as MongoDB Atlas on AWS, Azure and Google Cloud.
• Scaling. DynamoDB partitions data automatically. MongoDB scales out through sharded clusters that you or Atlas configure.

If you want MongoDB compatibility on AWS, Amazon DocumentDB (with MongoDB compatibility) implements the MongoDB API on an AWS-built engine. DynamoDB vs MongoDB compares the two databases in detail, and DynamoDB vs DocumentDB covers the AWS alternative.

Source: AWS DynamoDB documentation.