Features of Amazon SimpleDB are as follows:

Low touch: The service allows you to focus fully on value-added application development, rather than arduous and time-consuming database administration. Amazon SimpleDB automatically manages infrastructure provisioning, hardware and software maintenance, replication and indexing of data items, and performance tuning.

Highly available: Amazon SimpleDB automatically creates multiple geographically distributed copies of each data item you store. This provides high availability and durability – in the unlikely event that one replica fails, Amazon SimpleDB can failover to another replica in the system.

Flexible: As your business changes or application evolves, you can easily reflect these changes in Amazon SimpleDB without worrying about breaking a rigid schema or needing to refactor code - simply add another attribute to your Amazon SimpleDB data set when needed. You can also choose between consistent or eventually consistent read requests, gaining the flexibility to match read performance and consistency requirements to the demands of your application, or even disparate parts within your application.

Simple to use: Amazon SimpleDB provides streamlined access to the store and query functions that traditionally are achieved using a relational database cluster – while leaving out other complex, often-unused database operations. The service allows you to quickly add data and easily retrieve or edit that data through a simple set of API calls.

Secure: Amazon SimpleDB provides an https end point to ensure secure, encrypted communication between your application or client and your domain. In addition, through integration with AWS Identity and Access Management, you can establish user or group-level control over access to specific SimpleDB domains and operations.

Inexpensive: Amazon SimpleDB passes on to you the financial benefits of Amazon’s scale. You pay only for resources you actually consume. For Amazon SimpleDB, this means data store reads and writes are charged by compute resources consumed by each operation, and you aren’t billed for compute resources when you aren’t actively using them (i.e. making requests)