What is it?

ActivityPub is the glue or the oil, if you like, for the Fediverse. It glues all the services together in the Fediverse. It lets mastodon servers communicate with each other, but it also lets Pixelfed talk with mastodon and vice versa. All the social media that is ActivityPub aware can exchange messages with each other.

WordPress

WordPress is by its nature not ActivityPub aware. So, it can’t exchange messages with the Fediverse. But there is a solution. Matthias Pfefferle created a WordPress plugin to connect WordPress to the Fediverse. This enables you to get your WordPress posts across the Fediverse.

What do you need

1. Webfinger WordPress Plugin installed on your WordPress instance;
2. ActivityPub WordPress Plugin installed on your WordPress instance.

Setup

There is not much needed to get this working. Installed both plugins. The ActivityPub plugin has default settings that could work for you, but fiddle with them if you like. The Webfinger plugin doesn’t need configuration at all. When both plugins are installed, you will see it advises you for 2 more plugins. They are not needed to get ActivityPub working. But will enhance the experience.

Checking the setup

1. First check the Site Health under Tools > Site Health. If all is working correctly, you will get no critical errors on this page.
2. Go to the Webfinger website and check if you get a JSON response from your ActivityPub plugin by entering the e-mail address at the top. HINT: This is not your regular e-mail address, but the account name and domain name of your WordPress instance. So, if you have an account “Jake” on your WordPress instance at the domain “great.blog.com”, your “e-mail address” will be jake@great.blog.com. You can enter it at the top of the page. As a result, you should get a JSON response.
3. Go to your Mastodon account and search for your WordPress account (i.e., jake@great.blog.com) in the search bar of Mastodon.

Dos and Don’ts and Hints

1. Don’t install a cache enhancing plugin. It will mess with the ActivityPub or Webfinger Plugin. You will see critical errors after a while in your Site Health menu.
2. I found that [mastodon.social ](mastodon.social “mastodon.social”)messes with the avatar. It will not come through, even after a few posts on WordPress. I checked a few other mastodon instances (also mastodon.online, which is the other flagship server) they were fine. So, you should be careful with the mastodon server you choose to test this. It could make you think the plugin isn’t working properly.
3. Some hosting providers protect the .well-known directory. When this directory is inaccessible for the plugin. It will not work. (This made me host my WordPress instance at home).