Abstract: The present invention relates to a data mediation system and method. The data mediation system according to the present invention comprises: a plurality of things or devices; a consumer terminal registering data processing rules for generating customized data; and a data mediation server for generating the customized data by applying the data processing rules to data collected from the plurality of things or devices. According to the present invention, various pieces of data and information, which are generated during a service process through the things or devices and a web service mashup, are processed as various types of data and information so as to be mediated between a supplier and a customer.