Simon Willison’s Weblog

Where is all of the fediverse? (via) Neat piece of independent research by Ben Cox, who used the /api/v1/instance/peers Mastodon API endpoint to get a list of “peers” (instances his instance knows about), then used their DNS records to figure out which hosting provider they were running on.

Next Ben combined that with active users from the /nodeinfo/2.0 API on each instance to figure out the number of users on each of those major hosting providers.

Cloudflare and Fastly were heavily represented, but it turns out you can unveil the underlying IP for most instances by triggering an HTTP Signature exchange with them and logging the result.

Ben’s conclusion: Hertzner and OVH are responsible for hosting a sizable portion of the fediverse as it exists today.