Anything API infers what you want from the request structure and gives you a JSON response for any request. You can optionally specify exact return fields.

Try something like:

https://api.gyanl.com/ominous-8ball

https://api.gyanl.com/protein-calculator/1-boiled-egg?fields...

https://api.gyanl.com/color-generator?fields=hex%2Cname%2Cde...

I built this because it was an amusing idea, but it might actually be useful for some types of prototyping. Happy to hear thoughts and feedback!