Our API directory now includes 46 bitcoin APIs. The newest is the Btc.to API. The most popular, in terms of page visits, is the BitStamp API. Below you'll find some more stats from the directory, including the entire list of bitcoin APIs.
One of the cool things our directory data allows us to do is to get a glimpse at both short term and long term trends in the API space. One slice of data worth looking at is the categories have had the most growth. This article looks at which categories have grown the most in the last five years.