It’s very important for a website, and hence the server where the the web site is hosted to experience minimal or no downtime. Website and server uptime is important to ensure there is no lost revenue or profit, beside to ensure that interested viewers and surfers can access the website or blog without any downtime, network failure, system outage or connection failure in the hope that they will return to visit the site in the future. Users or visitors most probably won’t return again if the site or blog is always offline and inaccessible, and it will cause great annoyance and lose of trust.

In order to minimize server downtime or maintain highest possible website uptime and availability, it’s important that once there is any server outage, network disconnection or website downtime, the problem or the error have to be remedied immediately to bring back online the web server and website or blog. In order to know or to get notified whenever the website or server is down or having access problem, website monitoring or server monitoring service is needed.

Website server monitoring is the process of testing, tracking or monitoring how end-users interact with a website, blog or web application. The main purpose of website monitoring is to ensure that site visitors are able to access their online applications, websites or blogs, and perform actions such as searching, online shopping, checking an account balance, or simply researching and reading. The aim, of course it to avoid and minimize downtime and keep the server and online applications running. The commonly used benchmarks or measured metrics are response time and availability (or uptime), and with increasing popularity, consistency and reliability. Depending on service, web site monitoring can check HTTP, HTTPS, FTP, SMTP, POP3, IMAP, DNS, Telnet, SSL, TCP and a range of other ports and protocols at regular interval from multiple server located at different geographical locations.

There are several free website monitoring services and server monitoring services available online, some with options to upgrade for advanced monitoring and alert or notification services:

  1. SiteUpTime – Free account monitors 1 service from 8 monitoring locations at the frequency of 30 or 60 minutes with email alerts.
  2. HostTracker – Check the specified resource and service periodically according to the parameters of the monitoring set, and when an access error occur, the site will be checked by all other monitoring points; should these attempts fail, e-mail or SMS message (not for free account) notification of the problem will be sent. Maximum of 2 tasks and 2 contacts for free account.
  3. Internet Vista (no longer offer free service) – Light offer checks and monitors 1 server on HTTP pages every 60 minutes with email alerts.
  4. EControl (no longer available) – Free Internet web-based monitoring service provided to promote EControl Portal downloadable software, monitors and watches Internet services such as HTTP, HTTPS, PING, DNS, IMAP, POP3, RADIUS, NNTP, WEB CONTENT and AUTHORIZATION. When it detects that one of your internet services is not responding, it will send notifications to you at all of your designated contacts for that site.
  5. Pingdom – Reliable monitoring service with 20 free SMS text alert and 1 minute checking interval.
  6. Service Uptime – One monitoring service (any port or service) checked every 30 minutes from servers all over the world.
  7. ServerMojo – Monitor servers web, ping, dns, mysql and more approximately every 15 minutes. Free notifications by email and via Jabber IM server any time server is not responding, or optionally by SMS notifications for a small monthly fee.
  8. upPanel – Free website monitoring service that watches your websites and alert you if one becomes unavailable.
  9. WebSitePulse – Monitor the performance and status of your website HTTP server for free at interval of 60 minutes with e-mail and cellular phone notifications.
  10. Uptrends (no longer offer free service) – Free version checks 1 website every 30 minutes and provides detailed reports and alerts by email, RSS or IM.
  11. BasicState – Free uptime monitoring service monitors http and https services every 15 minutes for unlimited number of sites. Instant trouble alerts by email or SMS (premium fees).
  12. AlertFox (no longer offer free service) – Claims to be a evolutionary new website transaction monitoring service that is capable of keeping tabs on the function and performance of all websites, even those that use AJAX, Flash, Flex, and Silverlight. Free version offers 1 Firefox real browser test with a 4h interval, and 3 classic sensors with a 1h interval.
  13. Site24x7 – Free account monitors 5 basic websites from 1 location at a 10 min poll frequency.
  14. InternetSeer – 60 minutes check for free service.
  15. StatusCake – Unlimited checks at 5 minutes interval for free.
  16. Uptime Robot – 50 monitors checked every 5 minutes, totally free.
  17. Port Monitor – 2 checks every 60 seconds with unlimited notifications for free account.
  18. Pingoscope – 2 tasks, 50 SMS alerts, unlimited email alerts and up to one minute check intervals for free account.
  19. Monitority (not reliable) – Offers free, reliable and simple website monitoring with unlimited alerts via text sms, email and Twitter. No limits to the amount of services / URLs to monitor with sub-minute monitoring.
  20. Anturis – Free 5 monitors at 1 min polling period.
  21. Uptime Doctor – 1 test at 5 minute interval with 20 free push alerts per month for free service.
  22. Domain Tower – Provides more than uptime monitoring. Free account on Domain Tower also provides rank tracker, analytics integration and DNS manager for up to 2 domains.
  23. LeapZip Monitoring – New way of website monitoring by using HTML5 offline caching.
  24. GTMetric – Basic GTMetric (without Pro) is free and provides features like monitoring, graphing, ad blocking and more for up to 5 URLs.
  25. Uptimia – Provides free account which supports 1 uptime monitor from 5 testing datacenters at 5 minutes testing interval, with email alerts.

There are also downloadable standalone software program that can be installed on your own PC to do ‘in-house’ monitoring and checking:

  1. Nagios – Free, open source host, service and network monitoring program.
  2. Zabbix – Open source solution for advanced monitoring, alerting and visualization features.
  3. Paessler PRTG – Freeware edition is free for 100 sensors.
  4. Website Monitoring – Runs as service on Windows NT based system, and sits in the system tray, alerts you with an icon notification and an email if your website is down or running slowly.
  5. ManageEngine Website Monitoring (no longer free – alternative is ManageEngine Network Monitoring which may also perform the monitoring tasks) – Monitor performance and availability of websites using HTTP and HTTPS requests, from end-user perspective. Free edition allows 5 monitors in the network.
  6. URL Guard – A standalone program that monitor sites from system tray.
  7. Tiny Site Watcher – Monitor the status of any website or computer on the network and alert users visually, audibly and even by emails in the event the site or machine does not respond.
  8. Rushland Server Status – Display the status of services on any server.

Other paid website monitoring services, either web-based or desktop-based, are Dotcom-Monitor, Global Web Monitor (no longer available), Host Security (no longer available), Webmetrics, WatchMouse, Still-Up (no longer available), jaGuard (no longer accept registration), Alertra, , Woodstone Servers Alive, NodeMeter and Advanced HostMonitor.