The Octopus card is a rechargeable contactless stored value smart card used for electronic payment in online or offline systems in Hong Kong. Launched in September 1997 as a fare collection system for the city's mass transit system, the Octopus card system has grown into a widely used electronic cash system used not only for virtually all public transport in Hong Kong, but also for making payment at convenience stores, supermarkets, fast-food restaurants, on-street parking meters, car parks and many other point-of-sale applications. In addition the system is used for access control to offices, schools and apartments. It can even be used to donate money to charities.
Octopus has become one of the world's most successful electronic cash systems, with over 13 million Octopus cards in circulation and over nine million transactions per day. The operator of the Octopus system, Octopus Cards Limited, a joint venture between MTR Corporation and other transport companies in Hong Kong. Octopus's international arm, Octopus Knowledge Limited has won a contract to extend Octopus-style systems to the Netherlands.