Resources and further reading
Check out Microsoft API Guidelines as a good resource for REST API design and usage.
As an alternative to REST APIs, check out GraphQL. It's a project started by Facebook and then open-sourced.
There are various specifications which you can implement in your APIs:
- HATEOAS – Hypermedia as the Engine of Application State
- https://ionwg.org/ - The ION Hypermedia Type
- http://jsonapi.org/ - JSON API Specification
- http://json-schema.org/ - JSON (Hyper-)Schema...
This is a list of APIs you can use as samples: