Simple-yet-powerful features:
Multiple types
Check HTTP(s), ping, port and keywords.
Get alerted
Via e-mail, SMS, Twitter, push, Slack, HipChat, web-hooks...
Reach the stats
View uptime, downtime and the response times.
Verification
Verifies downtime from multiple locations.
Advanced notifications
Ignore minor downtimes by setting "alert once (or every x minutes) if down for y minutes"
Maintenance windows
Define time periods in order to not get monitored.
API
Perform almost every task with the REST API. Check the docs.
Public status pages
Share the stats with your teammates and/or visitors (demo).