How can I pass the access token to my embedded app with a dynamic URL?

[janarthanan]

I am developing a Shopify app to integrate a third-party app to store shop orders, products and customers.

To authenticate access to this third-party app, a GET request along with client ID, secret and callback URL is sent to the 3rd party app and it returns with the access token to the callback URL.

The issue comes here because, for dev Shopify apps, I get different URL from trycloudflare, so I can't use this domain for the callback URL. And if I am about to dynamically create the dev Shop URL for the callback, how can this shop URL pass the access token to my embedded app?