As Google released a similar (but better) tool, this one is not available here anymore. You can find the Google's AMP HTML validator here: https://validator.ampproject.org/ or in the iframe below.
Want to know more about AMP?
Here's a great guide by Paul Shapiro to get you started.
Pour les Français, WebRankInfo.com a publié un guide très complet qui répondra à toutes vos questions.