//-- your byte array you want to save var bytes: ByteArray = new ByteArray(); //-- set up correct url request using post in binary mode var request:URLRequest = new URLRequest ( 'http://pathto/save.php' ); var loader: URLLoader = new URLLoader(); request.contentType = 'application/octet-stream'; request.method = URLRequestMethod.POST; request.data = bytes; loader.load( request );