[mevile]

Does AWS Aurora actually use postgres or is it simply a postgres compatible API on top of their own technology?

[darkr]

As with RDS Postgres, it's Amazon's fork of Postgres.

With Aurora, the storage layer is swapped out entirely for a distributed storage engine, that I believe is based upon DynamoDB.

The wire protocol and server interface are much the same as regular Postgres, though there are some additional benefits as well as caveats as you might expect

[jadbox]

I'm pretty sure it's a fork of PG based on my experience.