How to create an always up to date alias for your Mastodon account

Mastodon is a new hot-trend topic, so I spent some time trying to wrap my head around it.

The decentralisation is an exciting part of Mastodon; if tomorrow I don’t like the instance where my account resides anymore, I can always switch to another instance and bring all my data seamlessly. It’s fantastic, except that now it’s like having another account with a different address, so I need to share it with my “audience” again and again.

Doing some research, I discover how to create a custom alias for my Mastodon account to have it always pointing to my current account; let’s see how!

How is it look like?

The alias I created for my account is [e-mail] where dlion is my nickname, and domenicoluciani.com is my custom domain.

If you try to search it on Mastodon, you will find my current account, which resides on mastodon.social

Behind the scene

I discovered that Mastodon uses ActivityPub to communicate between different actors and that those actors are found using WebFinger, a way to attach information to a specific email address or other online resources.

So I just needed to implement the WebFinger spec on my domain to have it working.

On your Mastodon instance, you have an endpoint called .well-known/webfinger, which accepts a query parameter that allows other Mastodon instances to get information around a particular account.

<youmastodonaddress>/.well-known/webfinger?resource=acct:<yournick>@<youmastodonaddress>

For instance, in my case, doing a curl GET request to this URL:

https://mastodon.social/.well-known/webfinger?resource=acct:[e-mail]

I get the WebFinger response for my account:

{
   "aliases" : [
      "https://mastodon.social/@dlion",
      "https://mastodon.social/users/dlion"
   ],
   "links" : [
      {
         "href" : "https://mastodon.social/@dlion",
         "rel" : "http://webfinger.net/rel/profile-page",
         "type" : "text/html"
      },
      {
         "href" : "https://mastodon.social/users/dlion",
         "rel" : "self",
         "type" : "application/activity+json"
      },
      {
         "rel" : "http://ostatus.org/schema/1.0/subscribe",
         "template" : "https://mastodon.social/authorize_interaction?uri={uri}"
      }
   ],
   "subject" : "acct:[e-mail]"
}

I need to put this response on my server under the same directory and inside the same file and that’s it.

How to do it on a Jekyll website

For my blog, I use GitHub for the hosting; specifically, I use github-pages which means using Jekyll, a static site generator.

To have your Mastodon alias in your custom domain using Jekyll, you need to:

1. In the root of your repo, create a directory called .well-known.
2. Inside the directory .well-known, create a new file called webfinger.
3. Inside the webfinger file, put the response you get when you curl your actual Mastodon instance WebFinger endpoint, as mentioned before.
4. In your _config.yml, add include: ["/.well-known"] to include that directory in your rendering.

And it’s done. Just push and wait a bunch of minutes. Your alias will be founded as [e-mail] by Mastodon, redirecting everyone to your actual account.

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References

If you want to know more about WebFinger, you can have a look at the original website of the spec and at the Mastodon’s documentation:

• https://webfinger.net/
• https://docs.joinmastodon.org/spec/webfinger/

I found out about this method thanks to this article by Maarten Balliauw:

• https://blog.maartenballiauw.be/post/2022/11/05/mastodon-own-donain-without-hosting-server.html