do you use WebAPI specification formats?

Do you use a formal specification for WebAPIs? Such as Swagger/OpenApi or JSON Schema or other formats?

Do you use it for documentation only or do you use it in code, e.g. for the validation of payload or other things?

Please help and fill the poll or leave a comment below.

Thanks for reading.

Comments

[rhymes]

OpenAPI, just for documentation

[Sven Kanoldt]

Thanks for sharing.

Would you appreciate a small tool that helps to generate validation code out of your OpenAPI specs?

[rhymes]

What do you mean? Validation of the API response?

[Sven Kanoldt]

Well more the payload in the response.

Imagine you are getting some json data, it often ends up in a dto.
But before it gets there the data must be validated against the API Spec so that the existence of fields and the format of the fields etc. matches the expectations.
And often even more it must be validated against some business rules once it passed the format checks. That is a lot of boiler plate and some logic in code is duplicated in the API Spec.