Cheeky answer: Land on Photoshop first. People underestimate the value of paying a designer for a high fidelity mock up and building a waitlist to see if anyon

Cheeky answer: Land on Photoshop first. People underestimate the value of paying a designer for a high fidelity mock up and building a waitlist to see if anyone actually wants your product - Real answer: iOS if you have the expertise, Web otherwise iOS : Network effect and people are willing to spend money way more than they are on Android. But development talent is harder to find than Web Web: Not quite as sticky for the kind of product that gets used on phones, but super cheap and easy to get talent for it. Android: Worst of both worlds, no one pays for anything, development talent is not as plentiful as Web and I think maybe even more limited than iOS? Source: Worked on top Android and iOS apps "back in the day", currently an embedded Android engineer working on HMI