I had an idea and is to create a frontend where the user can create a whole infrastructure using a react app for example that he can spin up, does this count towards open source and hacktoberfest initiative? Just something that came up to me when reading about the Automation API.

This would be really cool to see! @miniature-musician-31262 built an electron app that uses Automation API for something similar https://github.com/cnunciato/pulumitron

Yes, PRs merged to our examples repository will count toward Hacktoberfest.

What does that mean to "count toward Hacktoberfest"? Were there prizes or something?

Meaning if someone were participating in https://hacktoberfest.digitalocean.com/ and wanted credit

Oh, cool. I didn't know that was a thing.