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amphtml-validator Node.js Package

This package is published and available at

The source code is available at

Command Line Tool

The amphtml-validator command line tool is documented here:

Node.js API

This API is new - feedback is especially welcome.

To install, use npm install amphtml-validator in your project directory, or add amphtml-validator as a dependency to your package.json.

You may save the following example into a file, e.g., demo.js.

'use strict';
var amphtmlValidator = require('amphtml-validator');
amphtmlValidator.getInstance().then(function (validator) {
  var result = validator.validateString('<html>Hello, world.</html>');
  ((result.status === 'PASS') ? console.log : console.error)(result.status);
  for (var ii = 0; ii < result.errors.length; ii++) {
    var error = result.errors[ii];
    var msg = 'line ' + error.line + ', col ' + error.col + '' + error.message;
    if (error.specUrl !== null) {
      msg += ' (see ' + error.specUrl + ')';
    ((error.severity === 'ERROR') ? console.error : console.warn)(msg);

Now try running it:

$ node demo.js
line 1, col 0: The mandatory attribute '⚡' is missing in tag 'html ⚡ for top-level html'. (see
line 1, col 0: The parent tag of tag 'html ⚡ for top-level html' is '$root', but it can only be '!doctype'. (see

As expected, this emits errors because the provided string in the example, <html>Hello, world.</html> is not a valid AMP HTML document.

Release Notes



  • Added support for AMP4ADS (via --html_format command line flag) and argument for validateString function in the API.


  • Added support for --user-agent option.


  • Added newInstance method, a simple API that's not async.


  • Added support for installing on Windows. npm install -g amphtml-validator should now just work.


  • npm install amphtml-validator (local install) should now work on Windows, for require('amphtml-validator').


  • If the amphtml-validator command is already patched up for Windows, leave it alone instead of failing. Relevant if the package has been installed globally and now we're performing a local install on top of it.


  • Small tweaks to this file and package.json.


  • Set correct process exit status for old versions of Node.js (v0.10.25).


  • Better npm post-install for virtual machines, running debian over windows with SMB shared folder.


  • --html_format=AMP4ADS is no longer experimental.


  • --html_format=AMP4EMAIL added.


  • The amphtml-validator binary now requires the Node.js binary to be called node. On systems where the Node.js binary is called nodejs, consider installing the nodejs-legacy Debian package or better yet, NVM.