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Astro Cactus

Adding Webmentions to Astro Cactus

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  1. Add a link on your homepage to either your GitHub profile and/or email address as per IndieLogin’s instructions. You could do this via src/components/SocialList.astro, just be sure to include isWebmention to the relevant link if doing so.
  2. Create an account @ by entering your website’s address.
  3. Add the link feed to siteConfig.webmentions, found in src/site.config.ts.
  4. Create a .env file, or rename the included .example.env, and add the key WEBMENTION_API_KEY and set the api key.
  5. Go to and sign-in to each social account[s] you wish to link.
  6. Publish and build your website, remember to add the api key, and it should now be ready to receive webmentions!
  7. That’s it, maybe give this post a like!

What are webmentions

Put simply, it’s a way to show users who like, comment, repost and more, on various pages on your website via social media.

This theme displays the number of likes, mentions and replies each blog post receives. There are a couple of more webmentions that I haven’t included, like reposts, which are currently filtered out, but shouldn’t be too difficult to include.

Steps to add it to your own site

Your going to have to create a couple of accounts to get things up-and-running. But, the first thing you need to ensure is that your social links are correct.

Firstly, you need to add a link on your site to prove ownership. If you have a look at IndieLogin’s instructions, it gives you 2 options, either an email address and/or GitHub account. I’ve created the component src/components/SocialList.astro where you can add your details into the socialLinks array, just include the isWebmention property to the relevant link which will add the rel="me authn" attribute. Whichever way you do it, make sure you have a link in your markup as per IndieLogin’s instructions

<a href="" rel="me">GitHub</a>

Sign up to

Next, head over to and create an account by signing in with your domain name, e.g. Please note that .app TLDs don’t function correctly. Once in, it will give you a couple of links for your domain to accept webmentions. Make a note of these and head over to src/site.config.ts and add them to siteConfig.webmentions.

Quick note: You don’t have to include the pingback link. Maybe coincidentally, but after adding it I started to receive a higher frequency of spam in my mailbox, informing me that my website could be better. Tbh they’re not wrong. I’ve now removed it, but it’s up to you.

Adding your api key

Next is to add your api key, also from, to a .env file. Rename the .example.env, or create your own, with WEBMENTION_API_KEY= and then your personal key. Please try not to publish this to a repository!

Sign up to

You’re now going to have to use As the name suggests, it links your website to your social media accounts. For every account you want to set up (e.g. Mastodon), click on the relevant button and connect each account you want to search. Just to note again, currently has an issue with .app TLDs.

Testing everything works

With everything set, it’s now time to build and publish your website. REMEMBER to set your environment variable WEBMENTION_API_KEY with your host, I also forgot this part.

You can check to see if everything is working by sending a test webmention via Log in with your domain, enter the auth code, and then the url of the page you want to test. For example, to test this page I would add To view it on your website, rebuild or (re)start dev mode locally, and you should see the result at the bottom of your page.

You can also view any test mentions in the browser via their api.

Things to add, things to consider

  • At the moment, fresh webmentions are only fetched on a rebuild or restarting dev mode, which obviously means if you don’t update your site very often you wont get a lot of new content. It should be quite trivial to add a cron job to run the getAndCacheWebmentions() function in src/utils/webmentions.ts and populate your blog with new content. This is probably what I’ll add next as a github action.

  • I have seen some mentions have duplicates. Unfortunately, they’re quite difficult to filter out as they have different id’s.

  • I’m not a huge fan of the little external link icon for linking to comments/replies. It’s not particularly great on mobile due to its size, and will likely change it in the future.


Many thanks to Kieran McGuire for sharing this with me, and the helpful posts. I’d never heard of webmentions before, and now with this update hopefully others will be able to make use of them. Additionally, articles and examples from kld and really helped in getting this set up and integrated, both a great resource if you’re looking for more information!

Webmentions for this post

1 Mention

  • Webmention Rocks!

    This test verifies that you accept a Webmention request that contains a valid source and target URL. To pass this test, your Webmention endpoint must return either HTTP 200, 201 or 202 along with the appropriate headers. If your endpoint returns HTTP 201, then it MUST also return a Location header. If it returns HTTP 200 or 202, then it MUST NOT include a Location header.

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