I’ve had a look through the forum and some things have helped and some things haven’t.
I’ve been trying to call the API for a client project, and I’ve got it working with Postman (after the Auth, Username and colon issue people seem to have; I actually understand WHY that is an issue 
)
So, after re-creating the API for a Live site, Postman works great.
After tweaking the code on the local site, I can at least get response and not be blocked by bad authentication, or CORS (for CORS, I added the local dev site to the key settings).
Now, I did read there was an issue with localhost during my research, but I wondered if this was still the case. I’ve set up my local environments like proper sites (i.e. domain.local), so I’m not sure that is an issue.
Whenever I try to call anything, Postman retrieves it, but the AJAX returns 404.
Any ideas?