Backend Team

Like other people in this thread, we too have will have to rearchitect our solution to fit with your new requirements.

I get the feeling that the scenario you have in mind is one where the user in visiting a JS SPA and then clicks a link that will redirect them to an authenticated session in  Zendesk.

This might be the case for a lot of your customers. Our scenarion is quite different. We have forward request to help.ourcompany.com to ourcompany.zendesk.com at the DNS level, and after a couple of redirect theuser ends up in an authenticated session in Zendesk.

With your changes we have make som pretty radical changes. Probably turning the thing served att help.ourcompany.com into a mini SPA.

I would like to urge you to reconsider your decision. Or maybe, like some other posters have suggested, make the POST requirement optional.