Website downtime alerts and website monitoring worldwide. With the free plan you can monitor up to 60 websites every 3 minutes. Some nice features include checks after 1 minute of downtime before email alerts are sent - this helps prevent false positives so avoids being bombarded with emails if a website occasionally drops for a few seconds. SMS alerts are available on the free account but need to be purchased separately - SMSs are available to over 130 countries and 300 networks and the clear pricing system means you can tell exactly how much they cost. Stats of percentage uptime are given for 24hours, 7 days, 30 days and 90 days on the free account. The Pro account comes with some extra features - the ability to rate limit and customise alerts is useful. For example you can set it so that you receive email alerts only if a website is down for 5 minutes and an SMS alert after a site is down for 10 minutes. Repeat SMS alerts are also possible. Pro users receive a number of free SMS alerts depending on their account. With Pro accounts you can monitor up to 1000 websites and Enterprise accounts exist for bigger users.