When I worked at an internal Amazon team, we made heavy use of plenty of AWS services: MySQL on RDS, S3, and SQS for example. What we didn't use was EC2 et al.

When I worked at an internal Amazon team, we made heavy use of plenty of AWS services: MySQL on RDS, S3, and SQS for example. What we didn't use was EC2 et al. There was an internal equivalent for those.