Sweetfin is a free iPhone app developed by Sweetfin Holdings LLC, falling under the Lifestyle category and Food & Drink subcategory. The app allows you to order food and earn rewards and other perks.

To start using the app, you need to register your credit or debit card(s) in the app and place your order as usual. The app will notify you via phone when you earn a reward. You don't need to check-in or scan anything; just pay as usual. The rewards will appear on your phone, and you can use them at your convenience.

Overall, the Sweetfin app is an excellent tool for ordering food and earning rewards without any hassle. The app's interface is user-friendly, and the ordering process is smooth. If you're someone who loves to order food frequently and earn rewards, the Sweetfin app is definitely worth trying out.