General

Currently, the pulse monitoring payloads are displayed only in pages linked from a "downtime" page. I would find it useful if the last one was accessible from the "checks" page. My use case: I monitor a periodical backup of a DB, and put the S3 URL of the backup file in the payload. Being able to always easily access this URL would be nice.

I have some checks with a long period (1h) and sometimes need to ping them sooner than the period (e.g. after making changes to their hosting). Currently I have to change the period to something short, wait a bit for a probe to be sent, then remember to change the period back to 1h. I suggest you add a button "probe now" on each check, and maybe a button "probe all now" at the top of the "checks" page.

There is new kid on the block. Would be nice to have HTTT/3 indicator or test: https://en.wikipedia.org/wiki/HTTP/3

Allow maintenance window for planned IT job (server down)

Alert via automated voice call to multiple numbers

Add notification escalation. Add a method for responsible people to aknowledge reception of an alert. Add an escalation of alerts in case someone did not respond in due time (15 min, or parametrable).

Updown.io is one of the best services I have EVER interacted with! Thank you!

The random letters after updown.io (eg. updown.io/ngg8 ) should be customisable, especially if you use a brand name, for example ( status.mybrand.com/product )

Allows to monitor WebSocket only endpoint (ws:// and wss://)

I don't know why, but I always get confused if the far right is the current hour or the far left is the current hour. A mouse-over, tool tip or guide that just says "current hour" or "24 hours ago" would help clarify at a glance.