The Ukulele Chords API allows developers to query and publish ukulele chords diagrams (and/or additional infos like intervals, difficulty, etc.) on their website.
Ukulele-chords.com is a chord library with the largest selection of Uke chord charts in the most common tunings.
Eleven APIs have been added to the ProgrammableWeb directory in categories including Auto, Music, Visualizations, and Monitoring. Featured today are CloudViz APIs which can be used to generate diagram images from DOT based graph descriptions. Here's a rundown of the latest additions.