[Solved] Add 'Access-Control-Allow-Origin' header

Hi,
I’m writing a web app, which contains a simple form for easier wellness data input.
I want to build it as serverless app (no actual webserver with logic), but I encountered usual problem with API:

Access to XMLHttpRequest at 'https://intervals.icu/api/athlete/.../wellness?localDate=2023-02-07' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

So, I would like to ask you to add Access-Control-Allow-Origin: * header to API responses. If it’s not possible, is there any other way to make it without using a webserver?

nvm, I just need to use right url https://intervals.icu/api/v1/athlete/....

Yes the ones without the /v1/ are internal and do not support CORS. Mostly the internal ones have a corresponding /v1/ equivalent.