IMHO you need to distinguish between a start-up and an idea for a website: (01) A start-up is a business venture. It takes as input money, sweat and tears and

IMHO you need to distinguish between a start-up and an idea for a website: (01) A start-up is a business venture. It takes as input money, sweat and tears and can give you an output from a big loss to a few million dollars or more. (02) Your idea is actually for an on-line tool. There are actually many tools that can do this for you, google for example javascript beautifier or your language + formatter. Most professional programmers will also be working in IDE that automatically does that. I cannot actually imagine any programmer paying for this! By the way guaranteed, you will make zero money from Python developers!