The awesome-lemmy-instances repo on GitHub displays uptime:

• https://github.com/maltfield/awesome-lemmy-instances/

See this list of “Privacy-Conscious Email Services”

• https://prxbx.com/email/

I found this site that tracks uptime of lemmy services. They have an API that helps you construct a query in the WUI.

• • https://api.fediverse.observer/

Or you can use cURL to get the uptime of all known lemmy instances

curl 'https://api.fediverse.observer/' -X POST -H 'Accept: */*' -H 'Accept-Language: en-US,en;q=0.5' -H 'Content-Type: application/json' --data-raw '{"query":"query{\n  nodes (softwarename: \"lemmy\") {\ndomain uptime_alltime\n  }\n}\n"}'

See also:

• https://github.com/maltfield/awesome-lemmy-instances/issues/7

@mobiuscoffee@sh.itjust.works found one that monitors uptime!

• https://lemmy.fediverse.observer/list

Anyone know who runs that site? Do they have an account here on lemmy?