Fuck Swift. Such a garbage language. The last 3 days I tried multiple web server implemented in Swift for mocking API's and none of them worked. Old, not maintained, wrong documentation, wrong code examples and just low quality shit.
Finally I decided to not give a crap and move to use Wiremock and it works out of the box, start and configuration is a breeze and it just plainly works. I should have done that from the beginning.

Btw., as a warning these were the frameworks I used and you should avoid them if possible: Swifter, Embassy, Ambassador and Succulent.