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Why do some Pingdom Speed Test results show that Gzip is missing even when their web hosts are using Gzip compression?
Today we want to dive into how to use Pingdom Speed Test to test your website and explain why Gzip compression is missing in your test result.
What is Pingdom Speed Test?
Pingdom is now owned by SolarWinds Worldwide LLC in Austin, Texas, the USA. They offer website uptime and performance monitoring for better user experience. SolarWinds uses more than 70 global polling locations to test and verify their customers’ websites 24/7.
They built the Pingdom Website Speed Test to analyze website load speed and help optimize website speed by identifying website speed issues.
Together with PageSpeed Insights and GTmetrix, Pingdom Speed Test is one of the most popular website performance testing tools in the world.
Pingdom currently has seven testing locations around the world with one in Japan, two in Europe, two in the United States, one in Australia, and one in Brazil. Occasionally some locations are not available because the servers are too busy with many tests around the world. So, check back after some time or use another testing location instead.
Improve Page Performance
Under “Improve page performance” section, each category is given a grade from A (the best) to F (the worst) with a score, and suggestions which you can use to improve your website performance. The performance metrics include:
Compress components with Gzip
This reduces response times by reducing the size of the HTTP response. Gzip is a popular compression method.
Avoid empty src or href
This avoids browser behavior that could corrupt user data, waste server computing cycles generating a page that will never be viewed, or even cripple your servers by sending a large amount of traffic.
Put JavaScript at bottom
This makes JavaScript load last because JavaScript is render-blocking.
Minimize DOM elements
The Document Object Model (DOM) is an API for valid HTML and well-formed XML documents. Reducing the number of DOM elements reduces the size of a page to download.
Make favicon small and cacheable
The favicon of a website is a file (favicon.ico) in the server’s root. When the browser requests this file, the cookies for the server’s root are sent. Minimizing the favicon reduces the cookie size. Caching it avoids frequent requests.
Avoid HTTP 404 error
Making multiple HTTP requests and returning 404 (Not Found) errors increases load time and degrades user experience. Besides, if your favicon is missing, the browser returns a 404 error.
Avoid URL redirects
URL redirects are HTTP 301 and 302 telling the browser to go to another location. Redirects block rendering until the HTML document arrives.
Gzip vs Brotli
Gzip is a compression method first publicly released on 31 October 1992. It is used to reduce the size of text-based web files like HTML, CSS and JavaScript by 70-80% before sending them to a visitor. Gzip compression is enabled on the web server. The browser of the visitor will then automatically decompress the compressed files and serve the original files.
Brotli is a compression algorithm developed by Google and works best for text compression. It was initially released on 15 October 2013. As of today, over 94.5% of the browsers support Brotli. Brotli compresses files to a smaller size than Gzip so it is generally a better compression method than Gzip.
Our Pingdom Website Speed Test reveals that our website speed and performance test site got an F in the “Compress components with gzip.” If Brotli is used instead of Gzip on the web server your website is using, you may fail the Gzip test as in our case. Instead of Pingdom, you may use the Brotli Test Tool by KeyCDN to check if your web server supports Brotli compression instead of Gzip compression.
Conclusion
You can see now why your Pingdom Speed Test shows that Gzip compression is missing even though your web host is using Gzip compression. Therefore, it is crucial to better understand the data from Pingdom Speed Test and not to misdiagnose a problem as in this case.
