People with diabetes have been experimenting with and modifying their own diabetes devices and technologies for many decades in order to achieve the best possible quality of life and improving their long-term outcomes, including do-it-yourself (DIY) closed loop systems. Thousands of individuals use DIY closed loop systems globally, which work similarly to commercial systems by automatically adjusting and controlling insulin dosing, but are different in terms of transparency, access, customization, and usability. Initial outcomes seen by the DIY artificial pancreas system community are positive, and randomized controlled trials are forthcoming on various elements of DIYAPS technology.