Abstract: Systems, methods and computer program products that facilitate the token-based validation of contactless payment and other transactions involving NFC-enabled mobile devices are disclosed. In an aspect, the system includes a server and field-located validator devices to which consumers can present their NFC-enabled mobile devices in order to validate their purchases/payments. In one aspect, a consumer can purchase an admission ticket to a public transport system using their mobile device which communicates directly with the server to receive a token. The user can later present their mobile device to the validator device to actuate a turnstile. Advantageously, the validator devices do not have to be in real-time communication with the server, and limit the duration between the mobile device's request for a token and the time by which the token expires. Increased security is provided through two-way, token-based validation between the mobile and validator devices.