If you’ve ever tested your WordPress website using tools like GTmetrix, Pingdom, or Google PageSpeed Insights, you may have come across a warning saying:
“Remove query strings from static resources.”
At first glance, this might seem technical, but understanding and fixing it can give your site a noticeable speed boost.

In this article, we’ll break down what query strings are, why they affect caching, and how you can remove them effectively from your static resources to improve your WordPress site’s performance.

What Are Query Strings in Static Resources?

Query strings are the part of a URL that comes after a ? or &, usually used to pass information between pages or track versions. In WordPress, static files like CSS and JavaScript often include version numbers like:

In this case, ?ver=6.5.3 is the query string.

Why Do They Exist?

WordPress appends these version parameters to ensure that browsers load the most recent file whenever a plugin or theme is updated. It’s helpful for developers, but not always ideal for performance.

Why Are Query Strings Bad for Caching?

Some proxy servers and CDNs (Content Delivery Networks) do not cache resources with query strings, especially if the string changes frequently. This means:

• Your files aren’t cached properly

• Users have to re-download the same file

• Page load times increase

For better performance, it’s advisable to serve static resources without query strings and use alternative cache-busting techniques.

How to Check If Your Site Has Query Strings

Use any of these tools to scan your site:

• GTmetrix (https://gtmetrix.com)

• Google PageSpeed Insights (https://pagespeed.web.dev)

• Pingdom Tools (https://tools.pingdom.com)

Look for a warning like:
“Remove query strings from static resources.”
These tools will list the exact files causing the issue.

Methods to Remove Query Strings in WordPress

1. Use a Plugin (Easy Method)

If you prefer not to touch code, you can install a lightweight plugin such as:

• Remove Query Strings From Static Resources

• Speed Booster Pack

• WP Performance Score Booster

These plugins automatically remove ?ver= from CSS and JS files.

Best for: Beginners who want a quick fix

2. Modify Your Theme’s functions.php File (Manual Method)

You can add this code snippet to your active theme’s functions.php file:

Best for: Intermediate users with basic knowledge of WordPress code

This function checks if a query string like ?ver= exists in the script or style source URL and removes it.

3. Update Cache Settings in Caching Plugins

If you are using a caching plugin like:

• WP Rocket

• W3 Total Cache

• LiteSpeed Cache

Some of them provide an option to remove query strings from static resources directly in their settings.

Example in WP Rocket:

• Go to WP Rocket > File Optimization

• Look for “Remove query strings from static resources”

• Enable the option and save changes

Best for: Users already using caching plugins

Alternative Approach: Versioning Without Query Strings

Instead of using query strings, you can version your files by renaming them directly, such as:

And then enqueue them in your functions.php:

This way, the version is part of the filename itself, allowing proper cache-busting without query strings.

Things to Watch Out For

• Don’t remove query strings from dynamic files like AJAX endpoints.

• Test after making changes using performance tools to ensure no functionality breaks.

• Always take a backup of your functions.php or full site before applying code changes.

Final Thoughts

Removing query strings from static resources is a small but effective performance tweak that can lead to better caching and faster load times especially important for repeat visitors and mobile users.

While WordPress includes versioning for a good reason, for caching purposes and performance testing, removing query strings helps your resources be cached more reliably by browsers and proxy servers.

FAQs

1. Will removing query strings break plugin or theme updates?

No, but it may delay updates being reflected on the front end unless you manually clear cache or use file versioning methods.

2. Is this necessary if I use a CDN?

Yes. Some CDNs ignore files with query strings. Removing them ensures broader compatibility.

3. Can I automate this during deployment?

Yes, advanced users can set up scripts to rename and re-enqueue assets, but this is optional for standard WordPress setups.

4. Is there a performance gain on mobile too?

Absolutely. Faster caching benefits users on slower networks as well.

5. Will this affect SEO?

No, removing query strings has no negative impact on SEO. In fact, faster sites tend to rank better.