The main problem faced by sharia union is the lack of adequate IT and internet technology. This project aims to design and implement the system of SEWA~In App as an effort to improve financial inclusion in Samarinda City and to find out how Navigation, Performance, and Operational operate in SEWA~In App. The types of this research are qualitative research with descriptive method and modified action research with Test-Driven Development method. The data collection methods are interview, Focus Group Discussion (FGD), and questionnaire given to Samarinda society with random sampling technique using analysis tools namely Flowchart, Context Diagram, and Data Flow Diagram. The testing method used is black box testing. Black box testing was conducted in order to avoid errors or bugs in the application system. The test results show that (1) Based on black box testing in alpha and beta, the functionality of SEWA~In App can functionate properly without any bugs in the system, (2) In implementation stage, the value is 72% meanwhile in evolution stage, the value is 84% which is higher than the implementation stage, (3) Samarinda society has great interest in the use of SEWA~In App.