Instagram stopped answering our servers entirely. Capture now happens in your logged-in tab, which is both faster and far less likely to be blocked.
We used to queue an Instagram URL and let the server fetch it. That stopped working: from a datacenter address Instagram returns a logged-out shell with no post data in it at all, no matter which endpoint you ask.
So the work moved into the browser. The extension reads the data in your own logged-in tab and sends the finished post to us, and the server just stores it. It is faster, and it is the only approach that actually works.