Back pain is one of the leading causes of disabilityadjusted life year globally and the most common cause of low back pain is poor sitting posture. There are several actions that can be adopted proactively to avoid poor sitting posture induced back pain including behavioral change, regular exercise, and use of an ergonomic chair. However, these are either expensive and/or difficult to execute for prolonged periods. Sitting posture monitoring systems continuously observe the sitting pattern of a person in real-time and give feedback/alert poor sitting posture is observed. In this study, a real-time posture monitoring system has been designed and a functional prototype has been developed using simple electrical elements and an android application. Appropriate position of the sensor in the spine to measure the degree of bending and the threshold sensor values for good posture sittings have been determined based on the results from healthy volunteers of different ages and height. The android application continuously monitors the degree of bending and provides vibration when the bending reaches the threshold of bad posture or the duration of the sitting crosses the clinically recommended time limit to prevent prolonged sitting. Positive user feedback has been received in terms of comfortability, effectiveness, and satisfaction levels. The manufacturing cost of the developed monitoring system is minimal compared to the available expensive systems in the market and the cost would further go down if it is produced in bulk. This device efficiently monitors the sitting posture pattern to prevent back pain and within the affordable price range for the people from middle to under-developed countries.