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How-to: Site Speed Assessment and Web Performance Monitoring Tools


Site Speed and Web PerformanceYottaa is about web performance monitoring and web performance optimization. Besides Yottaa, there are many tools available for site speed assessment and monitoring. However, the market is chaotic. The business and technical approaches vary widely from one solution to another. A few weeks ago on a call, a customer told me that he is using 20 different web performance tools for his website. Shocking but not surprising.  In this post I will attempt to explain the different ways you can evaluate different tools.

1. Continuous monitoring or on-demand assessment

Some tools are designed to continuously monitor your website performance on a 24/7 basis while some are designed to perform a one-time performance assessment. Representative examples include:

  • On-demand assessment tools: and Yottaa
  • Continuous monitoring tools: Yottaa, Keynote, Gomez, AlertSite, WebMetrics and others

Keynote and Gomez have the longest history and are also probably the best known one. is a great service started by Patrick Meenan, who developed WebPageTest when at AOL a few years ago.

At Yottaa, we provide both on-demand assessment as well as continuous monitoring.  With, a user starts with a one-time assessment similar to, and then the user can choose to perform continuous monitoring.  For example below is a screenshot of the overview page for the Yottaa Web Performance Monitoring service for

2. By business model: open, closed, free or paid?

Web performance tools vary significantly from a business model perspective. Some of them are free and some of them charge tens of thousands of dollars. Some of them are open and completely available on a self-service fashion, while some however are only accessible after a sales engagement process.

Paid commercial offerings include Keynote Systems, Gomez, AlertSite, WebMetrics, etc. They typically charge a monthly subscription fee, ranging from a few hundred dollars to tens of thousand dollars. It’s important to point out that they do provide substantial value to justify the price they are charging. Web performance assessment and monitoring is complex, difficult and yet strategically important. From a return on investment perspective, paying tens of thousands of dollars to monitor site performance can be well justified from a business perspective.

As a relatively new comer, Yottaa is taking an open and free approach. We are able to do so because our business model is different. With Yottaa, a user simply goes to, types in a URL and  they receive an instant comprehensive report. Another example, which is ad-supported, is It’s is a great tool to use for performance assessment.

3. By geographic user coverage

Typical website performance monitoring tools are designed to monitor how users from different geographic locations would experience a website. However, most of the tools place monitoring agents at selected geographic locations and use the data collected by each agent to represent the user experience at the particular region. This is called “region level monitoring“.  The other approach is to measure the performance at a fairly granular level: measuring the performance for each individual user.  This approach is called “Direct User Experience Measurement“.

Yottaa provides region-level monitoring. Yottaa agents are real browsers running in selected regions such as Beijing, Singapore, US East, US West, Chicago, Dublin, London, Amsterdam, etc.  When you go to to perform Web Performance  assessment or monitoring,  Yottaa agents in these locations will visit your site and collect all the performance metrics. As a result, you will see how your site performs in US West, US West, London, Singapore, etc.

Direct User Experience Measurement: This approach typically requires embedding some JavaScript code on a web page to measure and collect page load performance data. An example provider of this technique is Gomez. The drawback of this approach is that the extra JavaScript code introduces its own performance side effect.  Yottaa is adding support for this feature. However  we are taking an innovative approach by piggybacking on Google Analytics to avoid performance side effects (see Yottaa blog post
“How to Measure Page Load Time With Google Analytics”).

4. By monitoring/assessment agent implementations

There are three different ways to implement the monitoring agent:

1. As a browser plug-in:

Firebug is the best known example available. This approach requires the user to download and install the Firebug browser plug-in and thus is typically used by web developers for testing and debugging purposes.

2. As real web browsers that run at different locations:

most web performance monitoring services work in this way, including Yottaa, Gomez, Keynote, and

3. As simulated browsers that run at different locations:

running real web browsers at different locations provides the best real user experience measurement, but it is more expensive and costly. As a result, some vendors choose to run server code that simulates a browser, which can be much more scalable and cost effective, yet less consistent and accurate.  Many  of the low end tools are implemented in this way.


Web performance monitoring tools help you assess and monitor user experience for your website or Web application from around the globe. There are a wide range of solutions available in the market.

Over the last year or so, we have spoken to many users that have used all of these tools and more – and they all keep coming to the same conclusion:  “There have been many solutions for years, but no solution has been sufficiently good for us so we ended up using a wide range of tools. It has been challenging and time consuming…If only there were one tool that just works without forcing us to jump through so many hoops…”.

We think there should be. We want to provide the best web performance tools and that’s why we started Yottaa. What Web performance monitoring tools are you using?  What would you like to see from web performance monitoring offerings?

Yottaa Ebook A Beginner's Guide to Web Performance Download


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