INS and diabetes mellitus: •Diabetes mellitus type 1 or 2•≥18 years old•Treated with insulin•HbA1c at baseline ≥7.5% and ≤11.0%•Not having used the investigated DiGA in the past 12 months•Willing to use a smart glucometer and/or smart insulin pen•Internet access, smartphone/computer compatible with the DiGA•Digital literacy to use a smartphone adequately