Here you can find a list of useful APIs. Some of them may require authentication, other will only need it to use some of the available features. Read the documentation for more information.
- MediaWiki
- Freebase
- DBpedia
- Google Maps
- Geonames
- Pleiades Places
- LastFM
- Vimeo
- Flickr
- Tumblr
- Visual Dictionary
- Cosm
- Twilio
- Foursquare
- SoundCloud
- YouTube
- BBC
- ViewChange
- Social Actions
- Wordnik
- Layar
- WolframAlpha
- Instapaper
- NASA images
- Hunch
- Netflix
- BBC Nature
- Tropo
- A list of various museum APIs
- A huge list of other APIs organised by category