Find Your List ID
To find the list ID for an existing Klaviyo list, navigate to the Lists & Segments tab of your account and click on a particular list.
The easiest way to find the list ID for your list is to look at the URL in your browser when viewing this list. In the URL, you will find a short series of numbers and letters -- this is the list ID. Every list has a unique ID, as does every user, flow, campaign, etc.
Switching Sign Up Forms from One List to Another
You will need to know a list's ID when you're connecting a sign up form. If you use Klaviyo's sign up form builder, the code that automatically populates includes the correct list ID.
If you delete a list or want to adjust a sign up form so that it adds subscribers to a different list, you will have to locate the list ID in the form code and swap it out.