The Bike Kitchen Bratislava (Cyklokuchyňa) and Cyklokoalicia started WhiteBikes in Bratislava after a failed attempt by the city to finance a similar program. At first users shared donated bikes with the same lock code. They needed a system that would work somewhat automatically without the need for manual rentals (e.g. somebody giving out bicycles). From there, smsBikeShare was born. Users registered with a mobile phone number and could send basic SMS commands (RENT, RETURN, FREE, WHERE, etc.). The system used an inexpensive SMS gateway API and a local message-back number to receive and respond to messages. Shared bicycles have a coded U-lock with a four-digit number, and upon renting a bike, users receive a code to unlock the bicycle and another to reset it to once they are done. Send a message, receive the answer, unlock the bike, reset the lock, and you're off pedaling.