TradTuneDb uses ABC notation and so obviously owes a tremendous debt to Chris Walshaw who developed it. It uses the MusicRest web service for storing and transcoding its tunes. This in turn transcodes by means of:

ABC to postscript: abcm2ps
postscript to various formats: convert
ABC to midi: abcMIDI

It uses the MIDI.js midi player to play tunes which have been saved to the database and the soundfont player from purescript-halogen-components for tunes played in the ABC editor and tutorial. It uses VexFlow for dynamic score engraving in the editor.

Code is written in scala and PureScript, with particular thanks to the following:

content negotiation: spray
web framework: play
interface to the mongoDB database: casbah
JSON: argonaut

The idea for the polska metronome was borrowed from Ben Potton of the band Jigfoot.