How to identify WordPress plugins with clean code

Choosing a WordPress plugin is easier when you know which signals to check. These checks help non-technical site owners spot maintenance, performance and compatibility risks before a plugin becomes part of the site.

8 checks for a reliable WordPress plugin

You don’t need to read every line of code. Start with the public signals, then test the plugin on a staging site before using it on a live website.

Check the last updated date

Well-maintained plugins are updated regularly. On the WordPress plugin page, look for:

• Plugins updated within the last 3 months
• Plugins that have not been updated for more than a year should be treated with caution

Look at compatibility information

On the plugin’s WordPress.org page, check:

• The “Tested up to” version, which should match the current WordPress version
• The required PHP version, because support for modern PHP versions is a good maintenance signal

Read user reviews with a purpose

Star ratings are useful, but the review text tells you more. Search reviews for these terms:

• “Slow” or “slows down”
• “Conflict” or “conflicts with”
• “Error” or “broken”

Repeated mentions of these problems can point to poor compatibility, weak testing or inefficient code.

Check loading speed before and after

Use a free tool such as PageSpeed Insights to measure your site before and after installing the plugin.

1. Measure the site before installing the plugin
2. Install the plugin on a staging site
3. Measure the same pages again
4. If page load time increases by more than 0.5 seconds, the plugin may be adding inefficient code or unnecessary requests

Look at what files it loads

After installing a plugin:

1. View your site in Chrome
2. Right-click and select “View Page Source”
3. Press Ctrl+F, or Cmd+F on Mac, and search for the plugin name
4. If the plugin loads many JavaScript or CSS files on pages where it is not needed, that can indicate poor asset loading

Check the plugin code online

You can inspect a plugin’s public code from its WordPress.org page:

• Open the “Development” tab
• Click “Browse the code”
• Look for an organised folder structure
• Check whether files are a reasonable size, rather than thousands of lines long
• Look for comments that explain the main parts of the code

Test for errors in real time

Check the browser console after installing the plugin:

1. Install the plugin on a staging site
2. Visit different pages on your site
3. Right-click, select “Inspect” or press F12
4. Open the “Console” tab
5. Look for red error messages that were not there before

Count database tables

Well-coded plugins minimise database impact:

1. Go to phpMyAdmin in your hosting control panel
2. Note how many tables exist before installing the plugin
3. Install the plugin
4. Check again. Good plugins usually add few tables, often between one and three

What to do before using the plugin live

These checks will not prove that every line of code is clean, but they will help you avoid plugins with obvious maintenance, performance or compatibility risks. If a plugin fails more than one check, test an alternative before adding it to your live site. For a related example, see our guide on what to test before replacing a form plugin.