HowFast monitors offers website downtime monitoring with a check every single minute. It also helps you to track the response time of your server over time, telling you how much time was spent during DNS resolution, TCP connection, TLS handshake, HTTP send / wait / download, and also following redirects.
Supports email and Slack notifications.
Slack team integration.
Nice uptime badges to add to your README. More Info »
HowFast is completely free, has a modern and elegant interface, and let you create up to 100 monitors.
Use it to get insights on your current performance, and see the impact of your changes over time.
HowFast also offers a nice histogram-based performance analysis tool.