Splitwise is a mobile app and web platform that helps people share expenses with their friends. Roommates, travelers, couples, and friends use Splitwise as a "shared ledger in the cloud." Friends enter shared bills, IOUs, and payments as they occur, and Splitwise tracks who owes who. Some people use Spliwise as a form of "karma" to see who should pay for lunch this week, while others settle up regularly every month using cash, check, or integrated online payment (provided by 3rd parties).