Wordpress Rest API

Standard

<?php
/**
 * Template Name: Custom API Endpoint

    # Updating views and storage 
    https://example.com/custom-api/?views=9435345&storage=2334242&site_id=2394&token=token_key

*/

// Capture query string as variables
$token   = $_GET['token'];
$storage = $_GET['storage'];
$views   = $_GET['views'];
$site_id = $_GET['site_id'];

// Define a random token to valid request. No symbols. 
$token_key = "RANDOM_TOKEN_KEY_HERE";

// Verifies valid token
if ( $token == $token_key ) {

    // Run custom code here
    if ($views and $storage) {
        update_field("field_57e0b2b17eb2a", $storage, $site_id);
        update_field("field_57e0b2c07eb2b", $views, $site_id);
    }

}