All you need to do to utilize the GUID as a Service API is make an HTTPS GET request to the API URL from your code:
This will return a brand new GUID created just for you as a String in JSON format, for you to use in any way you wish (as long as doing so complies with applicable laws).
For additional options, you can add any of these query string parameters:
This specifies what type of GUID to generate. Valid values are "1". which specifies creation of a Version 1 GUID based on timestamp and a MAC address, or "4" which specifies creation of a Version 4 GUID based on a random number. If not specified, you must not care what type of GUID you get.
Try it out:
If you specify this parameter, instead of returning a single String with a new GUID, generate the number of GUIDs you specify and return it as a JSON array. The number must be an integer between 0 and 1000 inclusive. Note that if you specify 1, it will still be returned in an array, even though only one GUID will be in it. (As opposed to when this parameter is not specified, where a single String is returned but not in an array.)
Try it out: