If your businesses relies off of a website, it is extremely important to choose a web host or servers that can maintain an uptime as close to 100% as possible, however even the largest sites have periods of downtimes. Definition: Uptime is the measure of the time a site has been “up” and running. It came into use to describe the opposite of downtime, times when a system was not operational. Uptime and downtime is typically measured in nines - five nines means 99.999% availability, translating to a total downtime of approximately five minutes and fifteen seconds per year. Generally, websites should try to achieve 99.9% availability, or roughly eight hours, 45 minutes, and 56 seconds per year.

Websites that have been down a long downtime record tend to suffer many other effects - centered around profits. When a site goes down, even for a few minutes at a time, potential customers visit the site and, unless you have grown your reputation/quality of services already, they won’t likely be returning. On the other hand, if your site had been running smoothly, there is a much greater chance that they would have been introduced to your site. Continuous downtime over large spans of time will also lead to the removal of your site from search engines, such as Google as the crawlers will be unable to find your site and any links or pages located in it.

I have compiled a list (in no particular order) of a few of the best uptime/downtime monitors. They all feature a free account option - allowing between 1-30 minute checks, up to 10 website profiles, and no limits to checks per month. In addition, you should read the terms of the sites - for example, if you use the free service, you must provide a link to their site. An uptime monitoring service with checks every minute is said to be the most reliable. However, none are 100% reliable, as their servers may go down or the check may not be active when your site is down.
 

1. Service Uptime - Service Uptime is a very reliable, professional free service which was established in 2004.

Free accounts include one monitoring service with a check interval of every 30 minutes. Every feature that is in upgraded accounts is also available in the free account, except with limitations dealing with number of sites you are able to track and the check frequency. In my opinion this site offers the most detailed and user-friendly interface out of any other uptime tracking site.

Other Benefits:

• Over 10 monitoring locations
• Full range of services and ports (from web page content to custom port)
• Summary statistics for the whole period of monitoring
• Web page Content and Partner Link Monitoring
• Uptime and Performance Reports - Daily, Weekly, Monthly, Yearly
• Public Statistics for One/Multiple Monitoring Services
• Ability to incorporate Public Statistics into your Website Layout
• Instant Availability check to verify your site is accessible
• Ability to send test Email/SMS Alerts
• Plus Many More Features!

If you need more frequent checks, you may want to take a look at their flexible pricing packs. For just $4.95 per month, check frequency can be as often as 3 minutes. There are other account options that will surely meet your needs. Before joining, you may take a look at their Reports Examples, FAQ, and Services Offered.

2. Site Uptime - Since 2003, SiteUptime has been providing website monitoring to (currently) more than 71,000 websites.

Joining the service with a free account will allow you to monitor one website, with either 30 or 60 minute check intervals.

Some features with this site include:

• 4 Monitoring Locations
• Online Statistics
• Monthly and Email Reports
• Web Server (http), Email (pop3/smtp), and FTP Server Monitoring
• Public Statistics

If you take a look at the Example Reports or the Demo Login, you will notice an extremely simple interface and control panel. In my opinion, the reports are provided if you need to quickly see if your site is up and running, not if you want to view detailed information about each downtime. Note: Requires a link to their site if using the free service.

SiteUptime features a “Quick Check” feature, which quickly checks your site from the four monitoring locations. Compare the Plans to see if the free plan is right for you. The service is slightly more costlier for the benefits than other sites - $10/month - with the Premium Plan to receive 3 website monitors and the optional 2 Minute Monitoring.

3. Host-Tracker - Providing uptime stats since 2004, Host-Tracker has one of the largest monitoring networks.

Host-Tracker has a very simple site, with almost no graphics. Now, that doesn’t mean it doesn’t offer detailed information about a site’s uptime. When a site goes down, you can view what type of error was reported and at what locations it was reported in. The main page offers a breakdown of the uptime for the current day, month,week, and so on, making it a lot easier for a quick breakdown on the important figures.

A summary of features:

• Monitoring periods every 1, 5, 15, 30, 60 minutes
• Possible monitoring of CGI scripts’ operation plus possibility to specify parameters to be passed to a CGI script
• Head, Post, Get HTTP-methods support
• Keyword presence control of a page, possibility to specify keywords by regular expressions
• Accumulation of statistics with further reporting
• Possibility to “open” reports on one or several of your resources to public
• No limit to report storage time and an unlimited number of addresses for server error notifications
• Time-zone adjustment enabled
• Reports accurate within days and the possibility to store check logs
• Error notifications both to your email address and to your cell phone via SMS

Prices range from $4.99 to $99.99/month, depending on number of monitored sites and check frequency. When joining, there is the option to have a 30-day free trial of an upgraded account. View additional features at Host-Tracker.
 

4. Pingdom - Hundreds of high-traffic websites are using or have mentioned Pingdom’s web site monitoring, including Alexa, CNET, and FeedBurner to name just a few.

Pingdom offers a 30-day free trial, with 20 SMS alerts included. They slogan is “Website monitoring made easy”. Their main monitoring service, called Pingdom, has one price - $9.95 for up to 5 websites at a one minute check resolution. Unlike their competitors, they don’t confuse you with different plans. For $0.50/month you can add 1 extra check (1 minute resolution) or extra SMS messages for an additional fee.

The Pingdom Panel offers a simple setup with graphs and logs detailing the uptime, and response times of your site. Interested? Check out the Features, Packages and Prices, and How it Works.

Pingdom’s GIGRIB distributed uptime monitoring is a unique service. How it Works: To monitor your website, you must first download (instructions) a small application that rests in next to your system clock, then you become a part of the network. For every hour of work your GIGRIB client does for the Pingdom network, you receive an additional five hours of uptime checks, accumulating up to 30 days of monitoring this way. The only obstructive element in this service is the client program - if it stops working you may lose some tracking time.

Features of the GIGRIB service:

• It is completely free.
• It is risk-free - no spyware or adware.
• Check frequency can be as often as once a minute or as long as one hour.
• Sites are checked from multiple locations.
• Add up to 10 websites.
• You are contributing to a project that will make the internet uptime statistics freely available to the general public.

5. Mon.itor.us and Monitis - Packing additional features besides website monitoring, these two companies (sister sites) offer professional, frequent and robust monitoring.

Mon.itor.us is a completely free version of the service, financed through online advertisements. Individuals, small and medium businesses, departments in large businesses, government and non-profit organizations may use this service. The site offers a new, unique approach to external and internal monitoring plus visitor tracking using “widgets” in a control panel page.

Monitis is a professional for mission-critical monitoring and ideal for users in need of more professional monitoring. With the purchase of any plan, you receive a a free 30-day trial. The plan structure is as follows: Personal, Personal+, Basic, Basic+, and Plus. Plans range from $1.98 to $39.98/month. Increases in global checks, internal checks, traffic watch, global locations, SMS Alerts, and the History all increase with account price. The free plan involves placing a back link on your site within 30 days of signing up.

What makes Monitis unique is the widgets, dashboard, and great features packed into every account. “Mongets” (small applications presenting live Monitis web performance data) can be placed within other pages and applications such as your Personal Google home page (iGoogle).

Both services offer a five minute monitoring interval with all accounts. Read more key features on their sites: Mon.itor.us and Monitis.
 

Other free monitoring sites:

• Montastic - “The best website monitoring service that doesn’t suck” featuring email notification when your site goes up or down, read statuses via RSS or Yahoo widget, fun, easy and elegant user interface, and no unreasonable limit on the number of websites monitored.
• Internet vista - Site checks every 60 minutes, with additional features.
• UpPanel - A website monitoring service that watches your website for any downtime, with advanced monitoring systems.
• Others: ServerMojo | Basic State