Market Helper Indonesia (MHI) is a mobile application proposal developed in 2018 by interior design students from 8-week class of Design, Society and Environment, at School of Design, Pelita Harapan University. MHI was first to answer a challenge from Perumda Pasar Jaya on why urban millennial as the potential future customers were reluctant to come to traditional market. This situation endangered the income of small traders and the existing of urban traditional markets. Therefore, MHI was created to solve these problems and has grown into a proposal to also solve healthy diet for families and fair trading for farmers and fishermen. This paper shows integrative design thinking and prototyping as the teaching method to help and encourage students to be creative in design an applied system, which is beyond their major study, to solve real problems for their environment and society.