Starting on 2016-09-14, we are adding a new IP block to the system.
The current IP blocks are still staying active and we’ll start to send requests from this new IP block too.
Here are the details:
IP Block: 18.104.22.168/28
which means that the IPs are:
And, the up-to-date list of the IPs can always be found in different formats at: https://uptimerobot.com/locations.