[heurist]

There are a few ways to start a software business:

1. Build a tool and start trying to sell it

2. Survey the market and figure out what's missing, then GOTO 1

When starting with 1 you run the risk of making something no one else wants and will likely need to substantially correct to market values. But if you want the tool to exist and are willing to build it purely for yourself, then you might as well build it. You'll be in a much better position for fundraising if you do, and if nothing else you can add it to your portfolio for your next job search.

Also keep in mind that markets do not need to be large to be profitable. Large markets can make reaching customers much easier but also starts you off as a blip in a sea of noise. If you can build something a few customers love, warts and all, then you're well on your way to viability.