GridSound uses many new HTML5 technologies, the main one is the Web Audio API which provides a powerful and versatile system for controlling audio on the Web. We chose to extract all the reusable Web Audio code into a standalone library: webaudio-library. The user's intial audio sample files have to be dropped into the app then into the samplegrid. For these actions we use the Drag and drop API, and for opening and read the files we use the File API. User Interface : We write our design with a modern CSS3 without any browser prefixes (eg : -webkit, -moz) and by using properties like transition and display: flex, the CSS is organised into different files using Sass (SCSS). The HTML part is separated into different templates, for that we use Handlebars. We use <canvas> to draw a live audio analyser of the master output, and all the audio waveform are drawn with SVG.