1.2.0 • Public • Published


A Node.js webmention verifier


npm install webmention-verifier


Webmention Verifier will mostly verify webmentions per the W3c specification. Mostly.

const wmverifier = require('webmention-verifier');

module.exports = async function () {
  const webmention = await wmverifier(source, target[, acceptableHosts]);

It will:

  • Verify that source and target are valid URLs (must)
  • Reject the request if source and target are not the same URL (must)
  • Perform a GET request on source and confirm source mentions target (must)
  • Handle arbitrary microformats (IE <a class="u-arbitrary" href="http://your-site.com">)
  • Handle sources with no microformats (added in v1.1)

It can:

  • Check if receiver is a valid resource to accept webmentions for target (should)

It wont:

  • Process the request asynchronously (more below) (should)
  • Limit the number of redirects during the GET request on source (should)
  • Store the webmention anywhere
  • Check source against a blocklist (I will add this at some point)


  • source: (String) URL of the source of the webmention
  • target: (String) URL of the target of the webmention
  • acceptableHosts: (Array of strings, optional) domains that are accepted by this webmention receiver. Should not include protocols (https://). Example: ['www.timculverhouse.com', 'timculverhouse.com', 'sub-domain.domain.tld']


Returns an object with properties:

  • statusCode: (Numeric) 400 for rejected webmentions, 200 for verified webmentions
  • body: (String) Description of the status code
  • webmention: (False || Object) False if rejected, otherwise a JF2 object (see below)

The webmention will be a JF2 object, which will have all discovered microformat properties, as well as:

  • wm-source: Equal to source
  • wm-target: Equal to target
  • wm-property: Equal to the type of webmention ("in-reply-to","like-of","arbitrary-value")
  • wm-verified: The date-time the webmention was verified

Synchronous vs Asynchronous processing

This verifier does all it's check synchronously. This is not recommended by the spec, but it is not capable of knowing how to form a location URL for you to respond to the sender with. So it doesn't do that.

It would be possible to add an option to have the verifier respond in an async matter (do what it can without fetching, respond with a code, and you handle the location URL crafting on your end while it finishes up verification);.


HTML (source = https://www.example.com/post.html, target = "https://www.duckduckgo.com"):

    <title>Single h-Entry</title>
    <article class="h-entry">
      <h1 class="p-name">Article Title</h1>
      <section class="e-content">
      <a href="https://www.duckduckgo.com" class="u-in-reply-to">DuckDuckgo</a>
      This is some content
    <a href="https://www.example.com/virginia-woolf.html" rel="author">about Virginia Woolf</a>


const wmverifier = require('webmention-verifier');

module.exports = async function() {
  const res = await wmverifier('https://www.example.com/some-post', 'https://www.duckduckgo.com');

/* Output
  statusCode: 200,
  body: 'Webmention verified',
  webmention: {
    type: 'entry',
    name: 'Article Title',
    content: {
      html: '\n' +
        '      <a href="https://www.duckduckgo.com" class="u-in-reply-to">DuckDuckgo</a>\n' +
        '      This is some content\n' +
        '    ',
      text: 'DuckDuckgo\n      This is some content'
    'in-reply-to': 'https://www.duckduckgo.com',
    'wm-property': 'in-reply-to',
    'wm-target': 'https://www.duckduckgo.com',
    'wm-source': 'https://www.example.com/post.html',
    'wm-verified': '2021-06-22T14:28:25.229Z',
    author: {
      type: 'card',
      url: 'https://www.example.com/virginia-woolf.html',
      photo: 'https://www.example.com/images/virginia-woolf.jpg',
      name: 'Virginia Woolf'

If we change the call to wmverifierto be a different target to trigger a rejection, we get:

var res = wmverifier('https://www.example.com/some-post', 'https://www.not-mentioned.com');

/* Output
  statusCode: 400,
  body: 'Source does not mention target',
  webmention: false

Things to do on your end

  1. Assign an ID webmention.io uses "wm-id" as the key, and I would stick with that. However you decide to do that is up to you (hash, increment, etc)
  2. Store your webmention somewhere A database, a file, anywhere.
  3. Check if the received webmention already exists, and act accordingly In theory, there should only be a single combination of target and source, so if you already have a mention to a target from a source, the newly received mention for that combination could be an update, a deletion, or a duplicate send. Don't store two, find the existing mention and act accordingly. I recommend adding a property on the first receipt of a webmention for wm-received, the date-time the webmention was first received. Webmention-verifier will update wm-verified every time the webmention is verified, which could be frequently depending on how senders send webmentions.
  4. Return the statusCode and body to the sender

Future Features

  • blocklist support
  • pingback support



Package Sidebar


Weekly Downloads






Unpacked Size

33 kB

Total Files


Last publish


  • rockorager