Background. There is little evidence available to better understand how mobile health application technology on mother and child health is designed. This study aimed: (a) to explore community health worker (CHW)/cadre and mothers’ activities information related with Posyandu, as well as inputs and feedbacks in developing the Posyandu mobile application, (b) to compare between training and implementation phases of the application, (c) and to see the potential use of the Posyandu mobile application in the country. Method. Using a hybrid method in which the action research principles and qualitative-quantitative methods were synergistically combined for the end users. The study was conducted in Pasawahan sub-district, Purwakarta, Indonesia from 2017 to 2019. Content analysis, coding and categorizing were done using NVivo 12 Pro for the transcribed data. Wilcoxon Test (2018 and 2019) was conducted using STATA 15 Special Edition. Results. (1) the use of CHW notebook for data entry in Posyandu information system book made a long delay in the data reporting process, thus, the development of mobile application would be necessary, (2) there were significant differences of CHW’s knowledge (p=0.000) and skills (p=0.0097) on training (2018) and Posyandu phases (2019), (3) As many as 964 posyandu are registered to Posyandu mobile application from almost all provinces in Indonesia. Conclusions. The 3-years hybrid approach suggests the crucial phases to build a mobile application in a more user-friendly manner that can replace the CHW’s old-fashion book use, and that it is promising for national use.