3-12 man months, assuming just 1 mobile front end. Like most software, it helps so much if you know exactly what you want to build and can plan ahead and not ne

3-12 man months, assuming just 1 mobile front end. Like most software, it helps so much if you know exactly what you want to build and can plan ahead and not need to make too many changes before you even ship. Constraining yourself to the smallest reasonable feature set helps you ship. Don't forget, you need to build both the frontend and backend. Software like this needs to be as asynchronous as possible and ready to fan-out, even if you know you wouldn't need to scale to 10M users from day 1. Use as many pre-built and vanilla UI components as possible. Custom UI slows down development by a lot.