AgentSlug.com is described as 'is simple but perspective application to monitor your website. For now, you can find there a full featured uptime monitoring tool. However, the app is developed constantly to provide complementary webmaster tools in the nearest future' and is a Uptime Monitor in the Network & Admin category. There are more than 50 alternatives to AgentSlug.com, not only websites but also apps for a variety of platforms, including SaaS, Android, Windows and Linux. Most alternatives are Uptime , Website Monitors and Network Monitors. The best alternative is UptimeRobot, which is free. Other great sites and apps similar to AgentSlug.com are Pingdom (Paid), Freshping (Free), Cabot (Free, Open Source) and StatusCake (Freemium).
Dashboard with 50 Monitors, Checked Every 5 Minutes, Totally Free. Monitor HTTP(S), Ping, Port and check Keywords. Get alerted via e-mail, SMS, Twitter, web-hooks or push. View uptime, downtime and response times.
Pingdom web site monitoring and other infrastructure for you and instantly let you know when anything goes wrong. Measure uptime, downtime, and the performance of your website as experienced by visitors.
StatusCake.com is a free website monitoring tool which allows users to track up to 10 websites and get alerted when their site is down or is having trouble. Downtime root cause analysis is included in the free plan to help users diagnose and fix issues.
Pingbreak is an original and free monitoring service. Get notified through Twitter if your website is down. Pingbreak checks all of your websites each minute and alert you instantly by Direct Message (DM).