Within a single document, a write operation to a DocumentDB cluster is atomic. A read operation returns only data that was durable before the query execution started, and does not return any data that was modified after. Dirty reads are not possible.
Logging is done via AWS CloudTrail, which logs all API calls by the clients as events. The most recent events are available on the CloudTrail console under 'Event history'. It is also possible to configure it so that the required details are stored in an Amazon S3 bucket.
DocumentDB can be accessed using a Mongo shell to create, read, update and delete documents. It can also be accessed programmatically using the MongoDB drivers for Python, Node.js, PHP, Go, Java, and C#.