Swagger is a tool implementing the Open API specification which defines a standard, language-agnostic interface for describing HTTP-based APIs.

x-ov-rules: culture: en rule: | the location of the applicant MUST be Dortmund

OAS 3.1 uses all of JSON Schema draft 2020-12 including unevaluatedProperties. You won't find direct references to unevealuatedProperties in the OAS spec because it links to the JSON Schema spec instead of duplicating it's contents.

This object is a superset of the JSON Schema Specification Draft 2020-12.

JSON Schema allows for additionalProperties both a boolean or an object value. true is interpreted as "additional properties follow no restrictions", false means "no additional restrictions", and an object is interpreted as a JSON schema applied to the property values (the empty object is thus equivalent to true).

Use a swagger or OpenAPI library to generate a schema and you’re pretty much doing what most people are doing.

there was a push for standardisation of “SOAP” (simple object access protocol) APIs

This is useful if just a subset of the operations need the API key

PI keys are supposed to be a secret that only the client and server know. Like Basic authentication, API key-based authentication is only considered secure if used together with other security mechanisms such as HTTPS/SSL