Edit and Upload Instagram Photos on Mac

This is against Instagram's Terms of Use. I don't know where exactly this is written but you are not allowed to use any third party client to upload pictures to Instagram. So this business is illegal... even bigger social media companies like buffer cannot upload to Instagram directly.

Instagram should have a native app for use on the mac that allows uploads. I'm really hoping they don't block this one from using their API.

Imagine back in 2000 if someone told you that in 2017 you would be able to pay 20 pounds for software that lets you upload photos to the internet (additional fees may apply) - and not only that, you can also crop and resize them and set a timer for when to do the upload. You'd think they'd never used a computer before!

How did this end up being a valuable thing that doesn't already exist on every phone and computer everywhere?

This will probably get your account banned. The feature list makes it look like it was built for spam purposes.

Don't use it on your personal accounts.

I bet this uses their undocumented API that allows uploads of media. If you use a traffic sniffer / HTTP Debugger like Charles, and use the Instagram app on your mobile device, you'll see that the native app is also using it's own API to upload media.