Ask Yoast stopwords in focus keywords

Ask Yoast
Why and how to minify your JS and CSS

Ask Yoast: why and how to minify your JS and CSS

November 21st, 2016 – 6 Comments

If you check your site speed with Google PageSpeed Insights you might get the advice to minify your Javascript (JS) and Cascading Style Sheets (CSS) files. Your JS files contain the code for the interactive elements of your website. And in your CSS files you specify the design of your pages. Minifying those files will decrease your page load time, thereby providing a better user experience.

We received a question about minification of JS and CSS files at Ask Yoast. Besides that, we also get the following question quite often when performing one of our SEO reviews:

“Why and how should I minify my JS and CSS files?”

Check out the video or read the answer below!

Become a technical SEO expert with our Technical SEO 1 training! »

Technical SEO 1 training Info

Minify your JS and CSS files

“JavaScript (JS) is the stuff that makes your web page interactive and CSS is the stuff that makes your web page look good. Basically, these two things are code that you send to the browser, and that the browser needs to render.

A browser, like any other computer program, doesn’t care what the language that it receives, looks like. It doesn’t need the spacing and the comments and all other stuff, that your developer needs to make sense of it all. He needs the structure to get through the code, however the browser has no benefit from that.

Stripping all of that down, actually makes the file that you send to the user a lot smaller. Because when you minify it, you remove all the extra spaces, all the line breaks and all the comments. Stripping all that, can save up to 30-40%, or even 50% of file size in some cases. There really is no benefit of sending that stuff to the end-users, so minifying saves time and money for everyone. 

That’s why you should do it. Good luck!”

If you’re on WordPress, there’s a vast amount of plugins that can help you minify your HTML, CSS and JS files. We generally recommend WPRocket for this and some further improvements to speed up your site.

Ask Yoast

In the series Ask Yoast we do our best to answer your SEO question! Need some help with your site’s SEO? Send your question to ask@yoast.com. You might get a personal answer on video!

Read more: ‘DIY: optimize your browser cache’ »


6 Responses to Ask Yoast: why and how to minify your JS and CSS

  1. John
    By John on 26 November, 2016

    Great information here, I agree it can be used. Yoast has helped with guiding our sites in the right direction.

  2. Patrick
    By Patrick on 25 November, 2016

    Thank you for your awesome plugin and your awesome articles. Greetings from Germany

  3. Willis
    By Willis on 22 November, 2016

    This has some great info here related to this article. I was thinking if you had any more info ?

  4. James
    By James on 22 November, 2016

    You had some great information here that I highly agree can be used. Yoast is a great tool that many of us can truly use

  5. Mike
    By Mike on 21 November, 2016

    Minifying CSS is one thing. Since most CSS files are pretty small, this will have a very subtle effect, if any. It is much more important to reduce the amount of CSS files. On fast connections server requests will significantly slow down your website. Minifying JS often breaks a site or some functions that need javascript. Test your website carefully after activating JS compression.

    • Jorge Villegas
      By Jorge Villegas on 22 November, 2016

      Excellent information thanks


Check out our must read articles about Technical SEO