John Marc spent nearly 13 years at Apple working on App Store technical policy, privacy initiatives, and helped ship iOS and iPad apps on visionOS and brought widgets to visionOS. He's given WWDC talks, collaborated with engineers across Apple and the developer community, and gained a deep appreciation for the gap between "this works in the demo" and "this ships to millions of users."

Now he's building Dewy Golf, an iOS app launching April 2026 that uses computer vision to automatically detect golf courses, recognize holes and using ML to detect shots automagically.. The technical stack includes segmentation models trained on satellite imagery, CoreML inference running on-device, and sensor fusion combining iPhone and Apple Watch motion data. It's the kind of project where you learn that training a model is the easy part; building the pipeline to do it at scale is where things get interesting.

John Marc is based in Colorado, and can be found at @ioloro across platforms. His talks tend to focus on the practical challenges of shipping real features to real users and building fun customer experiences.