The apertium pair viewer displays all apertium language pairs in an interactive graph. It was developed by Quincy Lam (reikaze) during GCI in January of 2013. While it's under development, it can be previewed at http://ilazki.thinkgeek.co.uk/~firespeaker/pairviewer/apertium.html and is available in SVN at http://apertium.svn.sourceforge.net/svnroot/apertium/trunk/apertium-tools/pairviewer/.
 A few bugs
There are a few apparent bugs that should be fixed before the pair viewer goes public.
- in initial view (sometimes?), quz has no line connecting it to spa
- sometimes two- and three-letter codes don't seem to merge
- when just trunk and staging are selected, tur/tr and nob/nb are each separate from one another
- when trunk, staging, and nursery are selected, nob/nb are merged, but tur/tr are separate
- when all possible pairs are viewed (including ones with missing stems, etc.), pa doesn't have a line connecting it to ur