The current waste problem can be said to be very worrying, there is a lack of public awareness in managing waste, especially managing organic waste. Organic waste itself actually has benefits if it can be processed properly, such as being used as organic fertilizer. This research aims to create a tool that can process organic waste into compost with the help of EM4 microorganisms automatically based on IoT. From the results of designing an IoT-based compost fertilizer system, it was found that the fertilizer produced was fertilizer with a pH level of 7.2, so it can be said that the system put together can be said to be successful, seen from the results of the fertilizer produced through the fermentation process. during the fermentation process, the methane gas produced on average ranges from 480 to 530. During the process, the highest methane gas is 571, the lowest is 473. This is caused by the fermentation process of organic waste with a biosater solution.