Using the API for commercial use/with ads

[Xariez]

Hi,

We're currently developing a web-app, which will allow the users to (without signing in) stream various podcasts (have gotten the green light from the owners of the podcasts themselves) on our site. Since this is, so far, for personal use (and only hosted on localhost) I don't see any issues with this, but as the goal is to get this published one day, with ads, I were wondering what kind of things will have to be thought upon while doing this? Will we still have to get an approval from spotify, or are we "flying under the radar" so to speak as we are not actively selling products on our site?

Any and all answers appreciated. Thanks!