How does a developer find a niche they can sell to?

Look for a room you've already been sitting in. The niche you can sell to is a group whose problems you've watched for years, in a place where some of them know your name. Being a member isn't enough; being known is.

The niche I didn't pick

My longest-running product reminds small landlords when their certificates and checks fall due. I didn't choose landlords from a list of niches. In my last 2 contract years I built internal tools for a firm that managed rented property, and at the start of that contract I joined 3 landlord groups online, to understand the people on the other end. I never left them.

5 years later a landlord with 4 houses, from one of those groups, asked whether I could "just do that for me", and offered to pay before anything existed. I built it that month.

Membership isn't standing

In my seventh year I built a tool that turned long supplier price lists into one comparison table, for an online group of people who buy supplies for small workshops. I'd belonged to the group for a year. I read it nightly. I'd posted a handful of times.

The launch met polite silence. 2 people paid, both people I'd helped before. The rest didn't know me well enough to try it. Being in the room isn't the same as being known in it.

A test for any niche

Count the people in the group who'd notice if you stopped posting. If the answer is under 10, you're a member. Become known first: answer questions, be useful, for months. Then build.

And check that the room has money in it. I once built a fixtures and results tool for people running amateur sports leagues, a group I knew well. Everybody agreed the problem was real. Nobody in the room had ever bought a piece of software.

Where to look

Your last job's customers. The groups you joined for a hobby. The forum where you've answered questions for years. The niche is usually already in your week. It just doesn't look like a market from inside.

Ship Alone has the niche sentence I use. Nobody Bought It has the price list comparer's autopsy.