What's this?
When you share a link on the Fediverse, most servers that receive the post will try to follow your link and generate a preview. This tool lets you see which servers followed the link to it, i. e. the servers your post reached. (For now, only Mastodon and Pleroma are supported.)
To use it, post the URL of this page (or generate a fresh one) on the Fediverse. Reload the page to see updates.
This page hasn't been fetched by a Fediverse server yet. Post the URL on the Fediverse and reload this page to see which instances have seen it!