Having your site online means that users may already be suffering slow download speeds on your pages. On the other hand, with the site online, you have the ability to truly test its effective speed.
I’ll get to a recommended list of testing services in a moment. No one service will cover every feature you want, which is why I recommend using the entire suite below. The services include:
Obviously, download time is the most important metric. Remember, download time must be less than eight seconds. Good is under five seconds, excellent is less than two.
Multiple sequential tests. Single downloads do not give a realistic appraisal of a site’s speed; five or more averaged tests give a far better understanding of a site’s performance.
Tests from multiple geographical locations. The speed of light still makes a difference, and any site, no matter what its focus, is international in scope.
Testing across different browsers, and different versions of those browsers (browsers have different effective download speeds for the same web page).
A “waterfall” analysis of requested resources for the site, including request and delivery time, allowing you to see which files are taking up the most download time, files that you can then target for optimization.
An ability to test at different connection speeds, including dial-up, DSL, and GSM.
Testing download speeds on different (simulated) mobile devices.
My favourite testing services, all of them free:
A very nicely designed site, with an airport terminal departure board aesthetic (which is actually more attractive than it sounds). Has every feature that I’ve mentioned above with the exception of the last two.
- Google Page Speed
Available as an online service or an extension for Chrome and Firefox, Google Page Speed is less a download timer than a site optimization rating tool. Tests run on a site receive a mark out of 100, together with a list of suggestions as to how download time might be improved.
A very thorough tester, with a rating for each site component, waterfall display, multiple tests, and a rating.
Uses Yahoo’s YSlow and PageSpeed (discussed below) to judge and rate your page. Allows comparison between pages, a speed rating of the web’s top 1000 sites, and a list of recommendations.
The same testing algorithm used by GTMetrix can be installed natively on your browser. The plugin has the broadest support of all of those mentioned so far: it’s available for Firefox, Safari, Chrome and Opera.
- Google Page Speed
An online tester that performs a high number of repeated requests of your site from New York City; can also test from the Netherlands. Otherwise similar features to the other tools mentioned above.
All of these tools will suggest many of the same optimizations I will explain in the subsequent articles of this series; unfortunately, all of them do so in rather complex and technical terminology. It’s my goal to take you through the simplest steps that yield the greatest result for time invested.