Leo Mehlig

Leo Mehlig (Leonard Mehlig) is a German app developer best known as the creator of Structured, a visual day planner that puts tasks, calendar events and focus sessions on a single timeline. He runs the app through unorderly GmbH, a small company based in Berlin.

Mehlig taught himself Swift and was a three-time WWDC scholarship winner, first invited to Apple's developer conference in 2015. He built Structured while studying computer science in Berlin, after struggling to organise his own busy student schedule and wanting a planner that also reminded him to take breaks. His friend Frederik Riedel, maker of the screen-time app one sec, is credited as an inspiration.

Structured launched on the App Store in March 2020. Instead of a calendar grid, it shows one day at a time as a colourful vertical timeline with suggested icons. By June 2022, when Apple highlighted him as a solo developer in its App Store Foundations Program, the app had passed two million downloads and close to $900,000 in revenue, with an optional one-time Pro upgrade and localisation into nearly 30 languages.

The app has kept growing since. Structured's website now cites more than 15 million downloads, over 500,000 Pro users and around 600,000 tasks created each day, with apps for iPhone, iPad, Mac and Apple Watch plus a web version. Newer releases added AI features that turn voice or text into a schedule, and the business has grown from a solo project into a small team.

Mehlig is a strong example of the student-to-founder path on the App Store: a self-taught developer who turned a personal productivity itch into one of the most-downloaded independent planning apps, without venture funding.