This site looks awesome, really cool to see what you're doing and I really hope it takes off! A little bit of feedback:

1. You really show offer a button in markdown format. The HTML one doesn't work on a github markdown document without losing all the styles because of github markdown security.

2. Because I had to use the image for markdown, I noticed that the image is pretty fuzzy on a retina screen. The whole thing is quite low res, might be worth doing a 3x one if you can?

3. It'd be great for a user to see the price they're donating and then just change it with a slide or input field. At the moment jus x1, x2, x3 is not only limiting but also quite hidden. A coffee in the UK is quite different to a coffee in Norway for instance. It also means someone can give much more if they'd like which is great for creators! Perhaps allow the creator to set a suggested and minimum donation, you can then cap at say $5 minimum, but have a suggested of $10 and the user can choose a value from there. If you wanted to keep the coffee analogy, you could have a nice little SVG which changes to a more extravagant coffee the bigger it gets, maybe eventually turning into a coffee machine at X amount.

4. I feel like I probably shouldn't be forced to setup a payment provider to get going, it makes it a lot more work to get up and running as a user of the platform.

5. It'd be fantastic if I could see where people came from when they donated. Perhaps they came from npm, github, or my blog, each is very different and lets me experiment with what's working and what's pointless.

Great platform, just what I've been looking for recently!