Customers use MongoDB as a document database to store, retrieve, and manage semi-structured data. However, it is hard to build performant, highly available applications that can quickly scale to multiple terabytes and hundreds of thousands of reads- and writes-per-second because of the complexity that comes with setting up and managing MongoDB clusters at scale. Amazon DocumentDB is designed from the ground-up to give you the performance, scalability, and availability you need when operating mission-critical MongoDB workloads at scale. Amazon DocumentDB implements the Apache 2.0 open source MongoDB 3.6 API by emulating the responses that a MongoDB client expects from a MongoDB server, allowing you to use your existing MongoDB drivers and tools with Amazon DocumentDB. Amazon DocumentDB uses a distributed, fault-tolerant, self-healing storage system that auto-scales up to 64 TB per database cluster. In Amazon DocumentDB, the storage and compute are decoupled, allowing each to scale independently, and developers can increase the read capacity to millions of requests per second by adding up to 15 low latency read replicas in minutes, regardless of the size of your data. Amazon DocumentDB is designed for 99.99% availability and replicates six copies of your data across three AWS Availability Zones (AZs). Customers can easily migrate their MongoDB databases that are on-premises or on Amazon EC2 to Amazon DocumentDB for free (for six months) with virtually no downtime using the AWS Database Migration Service (DMS).