Because Mastodon instances are separate, and different instances could be running different versions of Mastodon, your experience may not match these instructions exactly. However, the general parameters should be fairly consistent. XPoster has only been tested with Mastodon instances at version 4.2 and up.
That said, configuring XPoster with Mastodon is vastly easier than X.com.
Log into your Mastodon account & navigate to Preferences
There’s no central service, so you’ll need to go to the instance your account is on and log-in. From your account, navigate to the Preferences page. This link can usually be found in the Menu button near your profile:
There’s also a Preferences link in the side navigation panel:
Navigate to the Development settings
Preferences is a subsection of the Settings panel. In the Settings panel navigation, go to the “Development” link.
The direct URL to this page is https://your.instance/settings/applications. Replace ‘your.instance’ with the domain and TLD for your instance.
Create your application
Assuming you don’t already have an application you’d like to use, click on the “New Application” button.
Application name
Your application name can be anything; this is for your own reference.
Application website
This is also for your own reference; XPoster doesn’t make any use of it. However, it should probably be your WordPress home URL.
Redirect URI
Believe it or not, it’s another reference that XPoster doesn’t use. You can ignore it.
Scopes
Mastodon calls API permissions “scopes”. These are which API endpoints your new application will have access to. Currently, XPoster uses read:accounts, write:statuses, and write:media. Other APIs may be added in the future, but you can update your scopes at any point with a Mastodon application.
Submit your application
After setting scopes, hit ‘Submit’ to save your new application. You should land on the “Your Applications” screen with a table containing your new application.
Get Access Tokens
Click on your application’s name to get your access token or edit other characteristics of your application.
The access token is the only piece of application information you need to save in your settings in XPoster. Copy it from the application page and save it in your XPoster Mastodon API settings.
Instance URL
Because Mastodon doesn’t have a central server, you also need to tell XPoster where to send your API requests. XPoster only needs the root URL of your instance; it’ll fetch your handle when it verifies your credentials with the server.