Second job in Switzerland

Working in Switzerland as an emloyee for a company, I'm considering to maybe start a second job, as an individual business.

Would be something like create content to publish online (and get money from ads), or create an ecommerce website. Anyway, something that would be entirely managed from the internet.

Also, if I do it, I expect the income from the second job to be not so big, so founding a corporation on purpose (sa or sagl) would be inappropriate I guess.

In this cases, which one would be a convenient approach in Switzerland to legally declare the second income  and pay taxes over it?

I believe there are already a lot of people with a second job out there...

@benrunning Hi, I offer a business model that can be run part time, around a job and can be run from anywhere in the world.  You can check out my site:  [link moderated]

Reach out if you'd like more information.