YouTube Launches New API

YouTube migrated its API from REST/XML-RPC to Google Data so you can use the same package for accessing different Google services. The new API provides read-only access to user profiles, videos uploaded or bookmarked by a user, subscriptions, video comments, related videos, playlists, search results. And because the default output is Atom feeds, you can use the API to subscribe to a lot interesting data. Here are some examples of feeds that help you track a user's activity:

http://gdata.youtube.com/feeds/users/username/uploads - videos uploaded by username

http://gdata.youtube.com/feeds/users/username/favorites - videos bookmarked by username

http://gdata.youtube.com/feeds/users/username/playlists - playlists created by username

http://gdata.youtube.com/feeds/users/username/subscriptions - username's subscriptions

Some useful parameters for the feeds:

?max-results=50: the maximum number of items from a feed (by default, a feed includes only 25 items).

?alt=rss or ?alt=json: change the output format to RSS feeds or to JavaScript code (JSON) that can be easily used from web applications.

?vq=query: use this parameter to create a filter for a feed. Obtain only the videos that contain your query in the metadata (title, tags, description).

?orderby={updated, viewCount, rating, relevance}: sort the items from feed by upload date, number of views, rating or relevance.

Example of a feed:

http://gdata.youtube.com/feeds/users/google/uploads?
vq="google+maps"&orderby=viewCount (the videos about Google Maps uploaded by Google, sorted by popularity)

These feeds can also be used in applications like Miro to export your videos from YouTube.

{via YouTube API Blog}