https://blog.photopea.com/creating-photopea.html
He thankfully now makes a comfortable living from it.
It's one of my favourite indie-hacker-style stories, as the hacker was motivated by his intrinsic joy of making something.
https://www.reddit.com/r/IAmA/comments/9urjmg/i_made_a_free_...
I think this is less uncommon for bootstrapped companies than a lot of people assume. E.g. Patrick Campbell from ProfitWell has a similar story.