If you want to build a business and not side projects you need business development and marketing.

There is a bias(extremely wrong in my opinion) in HN against this and that product is everything but real world business doesn't work like that. Unless you have a viral product(which still needs marketing to reach critical mass) it is marketing that will make or brake it.

Also .io and other extensions might be trendy and fun to use but real businesses use .com . If you target end users they will hardly remember the tld of your website. How many services that end up in .io or other similar ones do you use?