Amazon DocumentDB (with MongoDB compatibility) is a fast, scalable, highly available, and fully managed document database service that supports MongoDB workloads. You can use the same MongoDB application code, drivers, and tools that you do today to run, manage, and scale workloads on Amazon DocumentDB and enjoy improved performance, scalability, and availability without having to worry about managing the underlying infrastructure.  

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/05/amazon-documentdb-mongodb-compatibility-now-supports-r5-instances-nvirginia-ohio-oregon-ireland/