I have a custom signup page that works great. I’m trying to pass a return url with a parameter for my custom thank you page. The signup and response to my site all work great until I add a parameter to the url and then the API behaves as if I had sent a blank return url and just displays the CC 200 success message and doesn’t perform the redirect. Just be clear
this works url=”http://mydomain.com/thank-you-message”
this doesn’t url-“http://mydomain.com/thank-you-message?subscriber=3434343”
Can anyone confirm if the API rejects parameterized return urls?
If I understand correctly that you're using the new POST URL to create contacts in your account, it should absolutely support parameterized URLs for the redirect. In this case the issue may be that certain characters are not being properly URL encoded, which can break the ability to parse the URL. For example, a URL encoded version of that looks like this: url="http%3A%2F%2Fmydomain.com%2Fthank-you-message%3Fsubscriber%3D3434343".
If that doesn't resolve the problem, it would help if you can provide any additional information or specifics on how you're implementing the signup form.