I've made an improvement to Downtime Monkey alerts.
Each downtime alert now includes a timestamp that shows the time that the website went down and each uptime alert includes a timestamp that shows the time that the website came back up.
This turned out to be more work than expected, largely because I thought I'd knock it out in under an hour :)
It required small changes to scripts the whole way through the monitoring system so although each change was straightforward, overall it took some time.
The end-result is identical timestamps included in all alerts (email, slack, SMS) that also match the downtimes shown in the downtime logs.
The main benefit is that you'll see exactly when the website was down, at a glance, as soon as you view an alert.
Full details on the blog: https://downtimemonkey.com/blog/timestamps-on-downtime-alert.php