StatusCake

You'll be the first one to know when your website is down. StatusCake monitors it up to every 30 seconds.

Description

StatusCake will monitor your site to alert you of any downtime. It gives you the option to decide how and when you get your alerts (email, SMS, push notifications for iOS & Android or third party integrations via apps including Zapier, PagerDuty, or Slack). Depending on your plan, your site can be checked for downtime every minute or every second. They also offer additional service related to downtime such as page speed monitoring, virus checking, and email templating for outbound alerts. Their free Community Edition offers a basic option for open source project or pre-revenue companies.

Price
FREE

Free plan is a community edition, with a slower check-rate and no advance monitoring.

Paid plans start at $24.49/month.