9.27API specification

In MuleSoft environments you'll commonly encounter:

RAML
OpenAPI

for API contracts.

Example:

/customers/{customerId}:
  get:
    responses:
      200:
        body:
          application/json:

The contract defines:

paths
methods
request schema
response schema
status codes

Then Mule implementation fulfills it.

Since you already know OpenAPI from testing, treat this as the same contract-first principle applied to Mule development.