Resource Definitions
OSS building blocks that wrap around your existing IaC. They let you design the infrastructure orchestration logic  of your platform.
Standardize your resource management
one-off 👉 reuse
In pipeline-based setups you need individual IaC files for every resource. This is very hard to maintain and scale with, leading to high change failure rate and security incidents.
Resource Definitions are declarative, code-based modules for I&O teams to describe how infrastructure should be configured and consumed by developers.
Integrate your IaC
Resource Definitions come with default Terraform modules baked in for reuse and as a starting point. You  can swap in your own or use any other IaC format such as Crossplane or Pulumi.
How it works
What are Resource Definitions?
Resource Definitions tell the Platform Orchestrator how to create/update infrastructure in a particular environment. A Resource Definition could for instance describe how all resources of type Postgres for environments of type staging should be configured. The Orchestrator will enforce that across all teams and workflows.
Resource Definitions + Orchestrator
Standardize your configs
Postgres DBs used in an environment of type staging should be configured the same way. Using resource definitions in combination with the Platform Orchestrator lets you enforce this by design. If the definition changes, all databases managed by this definition get updated automatically.