Build a Website for downloadin video and audio files from sites like youtube

Hi, i need to be done site like http://savefrom.net. Have to be 2 levels. Presentation (front end) and production (back end). Back end will be like php api that execute python script and get output (json) then convert to xml and send it to front end. Front end parse xml and show result. Transaction between front and backend have to be signed by token. All transaction have to be stored in mysql database and on home page to have last get movies. Have to be responsive, multi language. More info on private conversation. After web site was done there will have extra work that all to be converted to Android,iPhone app and browser extension.