How Can I Debug WordPress?

Debugging WordPress is not about trying random fixes until the site starts working again. It’s about narrowing the problem until you know what failed, where it failed, and what evidence supports your conclusion.

A WordPress problem can occur in many places: a plugin, a theme, custom code, etc. The best debugging process helps you explore these possibilities logically and systematically rather than guessing.

Start With the Main Symptom

Before you open logs or disable anything, define the problem clearly. For example, are you dealing with:

• A blank page?
• A fatal error?
• A slow admin screen?
• A broken form?
• A failed import?
• A layout problem?
• A button that does nothing?
• A checkout or account issue?
• A problem that started after an update?

Clarifying this is the first and most important step in the process.

Reproduce the Issue

Once you know the primary symptom, try to reproduce it.

Reload the page, submit the form, click the broken button, etc. If the issue only happens under certain conditions, write those down.

Pay attention to details such as:

• The page or screen where the issue happens
• The user role involved
• Whether it happens on the front end, in wp-admin, or both
• Whether it happens every time or only sometimes
• Whether it began after a plugin, theme, or WordPress update

This gives you a reliable test. Without a repeatable test, you may change something and think you fixed the problem when the issue simply didn’t appear that time.

Decide Where to Look First

Not every WordPress problem belongs in the same debugging bucket.

If the site shows a fatal error, critical error, or PHP warning, start with WordPress debug logging.

If the page loads but looks wrong, inspect the HTML and CSS in your browser.

If a button, dropdown, slider, or form action fails, check the browser console and network requests.

If the site is slow, look at database queries, server performance, background jobs, caching, and external requests.

If the issue appears only when two features are active together, you may be dealing with a plugin, theme, or script conflict.

This keeps the process focused. You are not “debugging WordPress” in general. You are investigating the most likely source of the specific problem.

Enable WordPress Debug Logging for PHP Issues

If the issue may involve PHP, enable WordPress debugging.

Open your site’s wp-config.php file and add the following code above the line that says /* That's all, stop editing! Happy publishing. */:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

This turns on debugging, saves errors to a log file, and prevents raw error messages from appearing publicly on your site.

After adding the code, reproduce the issue again. Then check the log file here:

/wp-content/debug.log

Look for recent entries that match the time you tested the issue. Useful entries often include a file path, line number, function name, plugin folder, theme folder, or error type.

If the path includes /wp-content/plugins/, a plugin may be involved. If it includes /wp-content/themes/, the active theme or child theme may be involved. If the path points to WordPress core, do not assume core is the real cause. A plugin or theme may have passed bad data into a core function.

Use Browser Tools for Front-End Problems

Some issues never appear in debug.log.

If the page loads but something looks wrong or fails to respond, open your browser’s developer tools. The Console tab can show JavaScript errors. The Network tab can show failed requests, missing files, blocked scripts, AJAX failures, or REST API errors.

This is especially useful for problems involving:

• Menus
• Popups
• Sliders
• Forms
• Filters
• Tabs
• Buttons
• Page builder interactions
• Front-end WooCommerce behavior

If the problem disappears after disabling caching, minification, or optimization, the issue may be related to how scripts and styles are being handled rather than the plugin or theme itself.

Isolate Plugins and Themes Carefully

If the evidence points to a plugin or theme, test carefully.

On a staging site, deactivate the suspected plugin or switch temporarily to a default WordPress theme. Then repeat the same test. If the issue disappears, you have confirmed that the plugin or theme is involved.

But that does not always mean it is the only cause. It may be conflicting with another plugin, the theme, a custom snippet, or a server setting.

Reactivate items one at a time and test after each change. Avoid disabling everything at once and then declaring the problem solved. That approach may hide the issue without identifying the cause.

Check Performance Separately

A slow WordPress site requires a different kind of debugging.

Performance problems may come from repeated database queries, expensive custom loops, background tasks that are taking too long, and similar issues.

For these issues, the PHP error log may not tell you much. You may need to monitor queries, server logs, request timing, and caching data instead.

A page that loads slowly is not the same kind of problem as a page that crashes. Treat it as a performance investigation, not just an error investigation.

Use WP Debug Toolkit for an Easier Workflow

You can debug WordPress manually, but the process can become scattered. You may need to edit wp-config.php, inspect debug.log, check browser tools, review database queries, and look at server-level information.

WP Debug Toolkit gives you a single place to examine most of these issues:

For PHP issues, you can review errors in its Error Log Viewer instead of scanning a plain text file:

For performance issues, you can use the Query Viewer to examine database queries and look for patterns that explain slow pages or inefficient plugin behavior.

WP Debug Toolkit also provides continuous error monitoring and recovery tools, so you still have a way to manage plugins and themes if a crash blocks normal dashboard access.

Clean Up After Debugging

Once you have finished collecting the information you need, return the site to its normal state.

If you enabled debugging manually, disable WP_DEBUG again so WordPress stops recording troubleshooting data unnecessarily. You should also review the log file and either save it for reference or remove it if it is no longer needed.

The purpose of debugging is to capture evidence while you investigate a problem. After that, keeping debug settings active on a production site usually creates more clutter than value.

Final Answer

How can you debug WordPress?

Start by identifying the symptom, reproducing the issue, and choosing the right place to look for evidence.

The goal is not to guess faster. The goal is to gather better evidence, make one change at a time, and confirm what actually fixes the problem.

For the most efficient workflow, use WP Debug Toolkit to bring error logs, query analysis, monitoring, and recovery tools into the WordPress dashboard.

For alternative plugins, see the 5 Top WordPress Debug Plugins.