The blooming development of smart phones and various mobile software applications has increased the dependency and need on smart phones. This is always a hot topic for all App developers how to optimize the service quality to improve user satisfaction and Loyalty. .With the basis of the PZB gap model of service quality and measurement model of service quality (modified SERVQUAL scale) from Parasuraman, Zeithaml, Berry (1988) , the study investigation is carried out with five dimensions of Tangibility, Reliability, Responsiveness, Assurance and Empathy. To collect the feedback of user satisfaction with the research subject of real-time traffic information app developers , 349 questionnaires were sent by social network and public street survey by developers. The valid questionnaires were 329. The research results conclude a gap that users have higher expectation relatively on the d service quality. The result also implies a positive correclation between overall user satisfaction and actual service quality. By the end this research, suggested practices in conclusion of research results analysis are provided for real-time traffic information app developers as development reference for related apps in the futureand to minimize the gap in service quality.