Dotabuff Github
Escolastico Hall
This is a counter picker for Dota 2. It shows the advantage percentages against a hero or team. Advantage percentages are collected from dotabuff.com. This tool simply adds advantages together and shows the sum of advantage of each hero. It updates database each day, so it will be always sycnhed with dotabuff.
DotaBuffCP designed to be a single page application. This allows you to quickly browse advantages. There is no page reloads, HTTP requests etc. You can instantly see the result and you can use this tool to counter-pick your enemies before matches.
It's also useful to browse advantages quickly. I was using well-known user voted counter picker website. It was slow, not up to date and everyone have their own opinion. I needed a stats based fast tool, and made this eventually.
Sadly its very poorly documented and hard to find info around. My best suggestion would be to look how open dota fetches it. The project is on github.
Theres also the valve wiki _Web_API you'll have to do some digging there to figure out which interfaces you need to call.