A QuickLook plugin for OS X for JSON files.
Download and unzip [QuickLookPrettyJSON.qlgenerator]
(https://github.com/tomnewton/QuickLookPrettyJSON/raw/master/install/QuickLookPrettyJSON.qlgenerator.zip) into /Library/QuickLook/
to install for all users,
or into ~/Library/QuickLook/
to install for yourself only.
To allow copy/paste functionality while in QuickLook, also run
defaults write com.apple.finder QLEnableTextSelection -bool true
from a Terminal window.
Embeds: https://code.google.com/p/google-code-prettify/wiki/GettingStarted js and suburst.css.