AppBeat Monitor Mobile!

Monitors your websites every 5 minutes, totally free. Get alerts by e-mail, SMS, Twitter or RSS. Add up to 50 websites. Monitors can be refreshed for an instant check with a click. Supports https and authentication with user/password.

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.

Comprehensive website and web application monitoring:* simulate a real browser (Firefox) to check performance* services monitoring (FTP(S), DNS, PING, TCP, SSL, SMTP, POP)* user experience monitoring (browser load time per user-agent, response time in various platforms* response time and throughput of each web transaction with graphical representation for quick performance insight* performance stats by ISP* application performance monitoring (monitor Java, .NET and Ruby on Rails web transactions and drill down to offending code and pinpoint root cause of issues from the cloud)* cloud monitoring (Amazon EC2, RDS instances and S3 Bucket)* VMware Monitoring* server Monitoring (Linux, Windows)* On-Premise Poller to monitor intranets* monitor from 3G/4G carriers* DNS server monitoring* SSL certificate expiration monitoring* notifications via SMS, Email, Push Notifications, Twitter and RSS Feeds* mail server, Exchange, FTP monitoring* API, user management* Root Cause Analysis - a comprehensive report based on trace route, ping output, DNS reports and web page screenshots that gives you a conclusion on what caused the issue »

Port Monitor is an easy and online tool that does website and server monitoring for you 24/7 every 60 seconds and sends you or your co-workers instant email/push notifications when something goes wrong.

Monitis is a Cloud monitoring and IT analytics service offering Website Monitoring, Server Monitoring, Network Monitoring, Application Monitoring, Cloud Monitoring, and Custom Monitoring.

Free open-source website monitoring software, easy to set up and use for monitoring web sites. You can monitor single web pages, multiple web pages, pages in sitemap and even your whole web site using spider. You can check HTTP result codes and even contents of the checked pages. Website checking is done periodically using build-in cron mechanism. In case of a check failure, application will automatically send email to site administrator.

Uptime monitor for server. Currently fully free (beta) so it is subjected to change. Allows to monitor unlimited servers and websites. With custom CNAME you can create live status pages.

Free Website Monitoring. Be notified when your site is down.

Monitority is a free & reliable website monitoring service that enables users to track unlimited services (websites, urls or ip addresses etc.) and receive alerts (via email, text-sms, tweet) when these services are not responding. Registered users can monitor as many services as they want and get alerts including worldwide free text-sms messages. Members can access Monitority via website interface or mobile app (iOS & Android).

Free & Simple website monitoring

Publisher notes:

FREE online web application that allows you to monitor your server/website: response times, availability, website statistics. Very easy in use even for non-technical people.

Monitor site uptime (not user-perceived load performance).