Instead of fussing with the API just visit the list within your account and copy the last bit of the URL. The URL will be something like the following. https://app.constantcontact.com/pages/contacts/ui#contacts/9f8a2e50-09d3-11ed-b739-fa163e6b8330 In this case the list id is 9f8a2e50-09d3-11ed-b739-fa163e6b8330
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