Our API directory now includes 531 reference APIs. The newest is the CanLII API. The most popular, in terms of mashups, is the GeoNames API. We list 88 GeoNames mashups. Below you'll find some more stats from the directory, including the entire list of reference APIs.
Less than two months ago, Merriam-Webster announced that some of its references would be available via an API. Now, competitor Cambridge University Press has followed suit with the Cambridge Dictionaries Online API. Currently, Cambridge offers five dictionaries through an API (i.e. Cambridge Advanced Learner's Dictionary, Cambridge Dictionary of American English, Cambridge Business English Dictionary, Cambridge Learner's English-Turkish Dictionary, and Cambridge Leaner's Dictionary).