Resource Types allow developers to define dependencies that their workloads have on things that need to be provided by the environment.
A Resource Type defines a type of technology without necessarily worrying about its underlying implementation. For example a
postgres resource type describes what properties a PostgreSQL database needs and how to access it, but does not concern itself with how the instance that provides the database is hosted or run.
Resource Types have schemas defining how they can be parameterised (inputs) and data that might need to be used by code (outputs.) In general, inputs are defined in deployment sets, and outputs are then used in Placeholders.