[apstyx]

I have not found a definitive source as yet and depending on the requirements of the task/project/client I have found the following sources excellent guidelines:

* https://stripe.com/docs/api/errors

* https://developers.google.com/search-ads/v2/standard-error-r...

* https://cloud.google.com/blog/products/api-management/restfu...

I love the Stripe API documentation.