This Shortcut takes a URL from a share sheet or the clipboard, and sends it to your instance of Postmarks, a social bookmarking service that runs on the Fediverse.

When added, you will be prompted for an instance of Postmarks - just the text of the domain (e.g. postmarks.glitch.me, not https://postmarks.glitch.me).

You'll need to be authenticated to Postmarks in your web browser of choice in order to use the Shortcut.