How to set up Twitter product cards
To set up cool product cards on Twitter, just take the following steps:
Go to Twitter's Card Validator tool, and click the Validate and Apply tab.
Enter your Gumroad product's URL. Here's how to find your product's URL, just in case you forgot.
And verify that all of its tags are approved.
Now the next time you tweet out your product, simply enter its URL and hit Send, and the product card will automatically pop up to your followers.