It is written in PHP, built on the CakePHP framework, and uses plugins from Anuj Sharma (CakePHP-App-Installer), Commerceguys (addressing, intl), Friends of Cake (bootstrap-ui), Jad Bitar (Footprint), Jevon Wright (html2text), Jose Diaz-Gonzalez (cakephp-upload, php-dotenv), Joshua Gigg (libphonenumber-for-php), Mark Scherer (cakephp-ajax), Òscar Casajuana (twbs-cake-plugin) and Trent Richardson (cakephp-scheduler). Unit testing is done with Sebastian Bergmann's PHPUnit.
Zuluru is based in part on Leaguerunner, originally written by Dave O'Neill, with contributions from Mackenzie King (bug fixes), Tony Argentina (player rating system, ladder-based scheduling), Dan Cardamore, Greg Schmidt (registration system, Google Maps layout editor) and Richard Krueger (iCal integration).
Contributions to the Zuluru codebase have been made by Mateusz Bocian (user interface) and Rizwan Jiwan (unit testing).
Feature suggestions and other inspiration have come from sources too numerous to remember.