How to organize API validation?

Question

PHP

Good afternoon!
Let's say we have 2 sites:

• example.com (angularJS)
  
• api.example.com (PHP)
  

How to send a request from the first to the second view

$http({
  method: 'GET',
  url: 'http://api.example.com/someMethod?param1=1&param2=2'
})

How to check api.example that we received a request from our base domain?
I thought that it was possible to pass some &key=mySuperHashKey along with the parameter, but then I realized that any fool could see it (provided that we only have JS (AngularJS) on the base domain))

Answer 1

Making direct requests there is not forbidden in any way with curl, for example.
And the browser can be "disabled" through CORS. Make a whitelist of domains.