LIONESS is an open-source software platform for online behavioural experiments including live interaction.

LIONESS only requires an active server to connect the experiment’s participants, who are interacting through their web browsers. The server software is developed using the most common and extensively documented scripting languages (PHP and HTML). These languages facilitate enormous flexibility in possible experimental designs, while their large community of active users ensures that most programming challenges are readily resolved through a Google search.

This page includes a kick-starter guide to get LIONESS up and running in just a few minutes. The Introductory tutorial shows users around the basic logic of using the software and the section Design experiments further explains how to develop designs and to run sessions on MTurk. Last but not least, we maintain Wiki pages with openly available, extensively annotated example program scripts for various types of experimental designs.