I hate visiting the dentist's office.

At the dentist's office we voluntarily allow someone to use sharp, metal tools (some of them powered) in our mouths to put us through unhuman pain and later reward us with bad news like: "Mr. Colbert, I have discovered a couple cavities" or "Mr. Colbert, did you know that your gums are receding?"

Getting poked and prodded by any doctor can make us uneasy but getting our website examined can be just as uncomfortable. Nevertheless, it is an indispensable requirement for living independently on the World Wide Web.

Therefore, Id like to share a few of my favorite website testing tools. These tools are like the MRI and EKG tests of the web:

1. Nibbler

Nibbler is a fun-to-use free tool that puts your website through a laundry list of 17 or so tests, returning a score for each one. It is a fantastic tool to get an all-round impression of the state of your website.

The resulting report summarizes the overall performance of your site in about 4 key areas: accessibility, experience, marketing, and technology.

Even cooler: Nibbler provides pretty good suggestions for how to fix any performance problems it finds.

Nibbler only tests 5 pages from your site so it gets less comprehensive as your site grows. (I guess that's why they call it Nibbler.) But how much can we really ask of a free tool? It really is quite a fantastic resource if you're just starting out with a one or two page site.

Also, some of the performance metrics Nibbler checks for may not be so relevant anymore. For example, it still checks to see if your site's URL appears on the long dead Google+.

  • PROS
    1. A great all-round tool
    2. Easy to use
    3. Provides a comprehensive set of metrics
    4. Provides excellent corrective suggestions
  • CONS
    1. Only tests 5 pages
    2. Some tests aren't relevant anymore

If you want to graduate to the paid version of Nibbler, check out Silktide

2. Google Page Speed Insights

Want to test how blazingly-fast your website is? Google's Page Speed Insights is a good start.

This tool grades your website on a scale from 0-100 on over 20 performance metrics. Some of these metrics are:

  • How long does it take before the first contentful paint happens?
  • Is your CSS minified?
  • Are your images properly sized?
  • Is there a resource that's blocking the rendering of your page?
  • If you are using webfonts is your text still visible while the webfont loads?

Your can use these metrics to shave precious milliseconds off the load-time of your page. This makes your page appear more performant. It tests both the mobile and desktop versions of your website too.

Furthermore, Page Speed Insights provides super-helpful suggestions and direction on how to squeeze more performance out of your site. Some of the suggestions are cutting-edge: like using next-gen image formats like JPEG 2000, JPEG XR and WebP instead of the old, faithful JPEG and PNG formats. The last time I checked Can I Use for JPEG XR it told me that only IE and Edge supported it. So… maybe some of Google Page Speed Insight's suggestions are a little too cutting-edge? Judge for yourself.

These tests are all about speed, so you'll have to use other tools to get a more rounded-out picture of the performance of your website.

  • PROS
    1. All about speed - Google keep a laser-focus on squeezing out every drop of performance from your site
    2. Easy to use
    3. Provides a comprehensive set of metrics
    4. Provides excellent corrective suggestions
  • CONS
    1. All about speed. You'll get no other impression on the state of your website with this tool
    2. Some speed-improvement suggestions might be a little too cutting-edge to be practical

3. web.dev Measure

Much like Nibbler, web.dev's Measure tool judges a page on your website on 4 main arenas: performance, accessibility, best practices and SEO. Your page is scored on a scale form 0-100 on all 4 areas.

Measure appears to be a super-set of Google's Page Speed Insights tool. So, this Measure gives you a more all-round impression of the state of pages on your website.

In addition to the pure speed-oriented metrics that Measure offers it also give you indications on things like:

  • How contrasty are the elements on the page? Can you improve contrast for visually-impaired users?
  • Are there any JavaScript messages/errors that are being generated client-side?
  • Do your links have a lang attribute?
  • Is your robots.txt file valid?

Much like Nibbler and Page Speed Insights, the corrective suggestions for this tool are very helpful.

The resulting report doesn't appear to be very comprehensive at first. You have to click on the "View Report" link to get the full report on your web page.

You may have noticed that I don't really say that Measure tests your website. It seems to just test a given page on your website. So, please bear this in mind. It isn't exactly a website-testing tool - it's a web-page testing tool.

  • PROS
    1. Provides a suite of tests performed on a page
    2. Provides a comprehensive set of metrics
    3. Provides excellent corrective suggestions
  • CONS
    1. Only tests a page not a whole website

4. Google Search Console

Honestly, I'm still trying to get my head around Google's Search Console. This tool tests the SEO performance of your website.

One interesting aspect of this tool is the relationship between the number of times your website has been seen in search results versus the number of times someone has clicked-through on those search results. So, Search Console can give you a good impression on the click-through-rate (CTR) of your website - how efficient those search results are in converting over to clicks.

This is a fascinating arena that you'd naturally step into as your website matures.

Search Console provides so many extremely interesting bits of information on these click-through-search events. For example:

  • From what countries have people seen links to your website?
  • What position in Google's search results is your website reaching?
  • From what queries is your web site appearing?

Search Console opens up a rabbit-hole of SEO tuning insights. Search Console doesn't seem to provide as much corrective guidance as the other tools do so you'll have to do your homework.

  • PROS
    1. A vast amount of information is collected on your website's search performance
    2. Opens up new insights on how people are reaching your site
  • CONS
    1. Not as straight-forward and easy to understand as other tools
    2. No corrective suggestions on how to improve SEO performance

5. Qualys SSL Labs SSL Server Test

Getting DNS and your SSL certificates working properly on your website can sometimes be challenging. Sometimes, the hosting provider you use might offer a free-but-limited certificate that only jams you up later.

Qualys SSL Labs SSL Server Test provides a very good indication of the SSL performance of your website:

  • How strong is your key?
  • Is your cert still valid? How long will it be valid?
  • Does your cert cover all the valid subdomains in your domain? Like, will it cover: my-domain.com and www.my-domain.com?
  • Is your cert trusted my Mozilla, Apple, Google, Windows?

The SSL Server Test will try to simulate handshakes from many, many platforms and give you the results of those handshake attempts. This help you understand if you'll have trouble with certain devices connecting securely to your website.

Even better: SSL Server Test will test your SSL setup against quite a few vulnerabilities.

It even rewards you with giant final grade from F- to A+ at the end of their tests.

  • PROS
    1. A comprehensive test of your website's SSL certificate setup
    2. Tests many potential browser/device platforms
    3. Tests against some SSL vulnerabilities found in the wild
  • CONS
    1. It's up to you to do your homework and correct any problems it discovers

6. Neil Patel's SEO Website Analyzer

Neil Patel's SEO Website Analyzer does a pretty good job of giving you an overall impression of the SEO performance of your website.

What's great about this tool is that it checks more than the 5 pages that Nibbler checks. That's cool.

The resulting report breaks down your website into a few key sections:

  • Healthy
  • Broken
  • Have Issues
  • Redirects
  • Blocked

You can quickly zoom in right to the aspects of your website's setup that aren't perfect.

It also provides an overall On-Page SEO Score for the highest-level overview of your sites SEO performance.

This tool highlights something called Organic Monthly Traffic and Organic Keywords. These are essentially non-paid keywords that have been harvested from your website's content. This is opposed to search results that have been paid for.

Want more? Neil Patel's SEO Website Analyzer provides a page speed analysis just like Google's tools. It also provides a prioritized list of improvements that need to be made to generate better SEO performance.

Understandably, if you make any changes to your website you'll have to wait a day or two before you re-check using this tool.

  • PROS
    1. I think it checks your whole crawlable site
    2. Provides a helpful speed-analysis result
    3. Gives good suggestions to improve your site
  • CONS
    1. (not really a con, just an understandable limitation): You have to wait a day or two before you re-check your website after taking corrective action.

I found Niel Patel's tool to be extremely helpful in improving my SEO

7. W3C Markup Validation Service

The W3C Markup Validation site is perfect for catching the structural markup issues that may be lurking on your website's pages.

Having a tool that 'lints' your web pages and saves you from code errors is especially important of your are building something more customized than simply using pre-canned Wordpress themes. If you're customizing a Wordpress theme, I would definitely consider checking the pages generated through your theme through a tool like W3C Markup Validation Service to catch problems.

I used this tool to catch a dangling element error in a custom template I had made for the blog entries on this site. In the process, I learned a few things about what sub-elements are considered required under parent elements. For example, I didn't know that <H[2-6]> elements are considered basically mandatory under a <SECTION> tag.

  • PROS
    1. Finds required adjustments to your site based on W3C standards

Because of the nature of the tool I couldn't think of any CONS for the W3C Markup Validation Service. It's basically a must-use service if you don't already use a HTML5 linter.

8. Mozilla Observatory

Mozilla's free tool helped me to discover a security issue on my website that led to the implementation of an excellent HTTP header security tool. This has vastly improved overall security of my website.

Observatory tests cookie security, CSP, redirection, HTTP Public Key pinning and so much more. The interesting thing about Observatory is that it consolidates scores from a few other security testing tools such as:

These tools focus heavily on HTTP header and SSL security.

Observatory sums up these 3rd-party tests and gives you a consolidated total score with helpful tips to improve that score.

Although I don't list ImmuniWeb separately here in this blog post I was really impressed by what it tested for. It focuses heavily on PCI and HIPPA compliance as well as industry security standards checking.

Mozilla Observatory and its friends are thorough and will most certainly impress upon you that security is a vast and expanding landscape. It's like an MRI for your website.

  • PROS

    1. Security-oriented test
    2. It's really a suite of tests from several heavy-hitter test tools
    3. Discovers deep security threats and weaknesses
  • CONS

    1. Discovers deep security threats and weaknesses - you might have to really roll up your sleeves to correct these errors. But, of course, it's worth it.


Putting your website through all of these tests is like showing up to a hospital and telling them: "Do your worst." All of the discomfort, fear and pain will only yield something concerning, something that must be corrected post-haste.

Although no one likes to receive a less-than-stellar grade for their physical health or their website's health, it's the only way to truly discover what you need to work on.

So, if you're keenly interested in improving your website's performance then don't hesitate to give these free tools a try!