Electricity usage monitoring systems play a vital role towards raising energy utilization awareness for consumers. Existing solar mini-grid infrastructure, however, lacks a user-friendly two-way platform to allow consumers to access information about electricity consumption. This paper proposes a cloud-based, two-way energy usage monitoring system that will allow both utility companies and consumers to access energy consumption data in a user-friendly way through a web platform. The system requirements were collected via questionnaires, interviews, and observations conducted at two solar mini-grids centres located at Arusha and Kilimanjaro regions in Tanzania. The system uses a Low Power Area Network (LPWAN) and the existing GPRS network to monitor electricity consumption data between smart meter units and the cloud server. Also, a virtual bill payment module and usage status feedback functionality have been integrated into the system to increase awareness of the cost-effective use of electricity and hence, achieve the sustainability of solar mini-grids. By using both white-box and black-box system testing approaches, findings show that the system will not only raise awareness among customers about the economical usage of electricity, but it can also be used by mini-grid companies as a source of data to determine current and future energy demands to minimize large investment costs.