How can i get API key for a tool based website?

I actually want to develop a tool base website so i want to know that how can i get API key to fetch all the data from any website?

for example i want to get API key of (link removed).

I think you’re not asking on the right forum. and I removed the link from your post. Our API is focused on displaying 3D graphics, and I think your question is about other types of APIs?