ReGo: Research on the go! is a tool for user-reported data collection. This app is a complement to our data collection portal (https://researchonthego.eu). It can be used for experience sampling, as digital diary, or as a tool for patient-reported outcomes or patient-reported experience measures. ReGo helps researchers and health professionals to conveniently and safely collect data that reflects the daily experiences of their customers. Choose from several measurement instruments, including visual scales, numeric scales, sliding scales, multiple choice or free text input. The app notified the user when it is time to answer a questionnaire. Both fixed schedules and randomized schedules are supported with great flexibility.