O2O service platform that provides offline to mobile connection services. Stamping on the phone connects with Echoss cloud service and enables a variety of mobile services. The stamp service employs a multi-touch recognition technology that can be applied to all smartphone users. The Echoss platform is composed of: physical stamp to be exhibited on site, the certification center and the information center. As the Echoss smart stamp sends information via the touchscreen of phone, a SDK is provided to enable application or mobile web service. The identification of the Echoss smart stamp entered through touchscreen is certified real time at the certification center, a 12CM cloud service which provides security and fraud monitoring. The Echoss information center receives data and systematically analyzes information about phone, user, stamp, location and time so that the data can be utilized for various O2O services.