“If you're a developer and you want to make a go at being an indie developer and making a good living on the app store instead go the opposite direction go really really niche but in a niche that people are willing to spend money and that people find valuable.”

Go Really Really Niche — Find an Audience That Happily Pays

The indie app winning strategy is extreme niche focus — not a narrow niche, but a niche where spending is already normalized. Hobbyists, professionals, and enthusiasts who spend thousands on their interest in the physical world will pay $10-50/year for a great app in their domain. The goal is to find where people already spend freely, then build the obvious app for that community.