Hi, is there a way to get a fixed return URL from get_notify_url()?

No. It will always return an ACT + randomized encrypted string URL. To get a fixed return URL, either manually set a URL, or use the extload functionality.

instead of get_notify_url, use:

That will output a URL that does not contain any query string variables. It’ll look something more like: yourdomain.com/extload.php/yourgateway

Open up extload.php in the themes/third_party/cartthrob/lib folder and take a look at the first few lines in there. You’ll need to configure your system path and themes path if they have changed from the default.

Thanks Chris! It works like a charm

Quick note, in case anyone else having the same problem in the future.

The response function in the payment gateway class should be named extload() in order for the extload.php file to call it.