DynamoDB is useful for services that are likely to have a very large amount of load and require minimal maintenance. For example, Mozilla uses DynamoDB to back

DynamoDB is useful for services that are likely to have a very large amount of load and require minimal maintenance. For example, Mozilla uses DynamoDB to back it's browser push notification sending service. It would be better if it supported SQL, like Google Spanner, but it's still useful. Redis is useful because it can do so goddamn much. Caching, task queuing, hyperloglog, geospatial indexing. Set it up once, and it can replace a very large number of cloud services. And it has a lot of options for replication, backups, clustering, etc. It is like a Swiss army knife.