Simple direct link, e.g: https://yt2audio.com/convert.php?id=YOUTUBE_VIDEO_ID Change YOUTUBE_VIDEO_ID with your Video ID
This API is FREE for non-commercial! you can embed this iframe code to your site <iframe src="//save.yt2audio.com/convert.php?id=YOUTUBE_VIDEO_ID&title=VIDEO_TITLE" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" height="70"></iframe>