If you've made the previous Transactional call and the contact doesn't exist on the short code and list, you can create the contact with the Create New Contact call.
Following the steps to create a contact, you will make and subscribe a contact to a list that was passed in with the call.

1. Open in a tab.
2. Navigate to Create Contact.
3. Copy the relative Create Contact URL from the right-hand side of the page.

4. Navigate to Postman.
5. Paste the relative URL in the address bar.
6. Select POST from the drop-down menu.
7. Enter the Contact Details in the body of the request

8. Click Send.
You've now created a new contact to be subscribed to your list.

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