Status
Subdex runs entirely in your browser, so when something stops working it is almost always an archive source rather than the site.
Subdex frontend
Static files. If this page loaded, it is working.
Available
Arctic Shift
Primary archive source.
Not checked
PullPush
Fallback archive source.
Not checked
Checks run only when you ask. These are free services and polling them on a schedule would cost them bandwidth for no research benefit.
If a source is down
Saved research, the workspace and every informational page keep working, because none of them need a network. Only new searches are affected. Archive operators publish their own status pages, listed on the sources page, and neither offers an uptime guarantee.