The document discusses how the Qovery deployment engine works. It is written in Rust and uses a state machine approach to deploy applications across multiple steps in a transactional manner. It pulls deployment requests from a control plane and executes them on user AWS accounts, building and deploying containers through APIs. The document also provides an overview of Qovery and how developers can use it to deploy apps on AWS, as well as suggestions for getting started with the Rust programming language.