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WordPress13 April 2026

How to Debug WordPress Errors Like a Developer

When your WordPress site breaks, random guessing wastes time. A structured debugging process helps you isolate issues quickly.

Enable Debug Mode

Edit your wp-config.php file:

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

Logs will be saved in:

/wp-content/debug.log

Identify Plugin Conflicts

Most WordPress errors are caused by plugins.

Steps

  1. Disable all plugins
  2. Re-enable them one by one
  3. Identify which plugin causes the issue

Switch to a Default Theme

Temporarily switch to a default theme like:

  • Twenty Twenty-Four

If the issue disappears, the problem is your theme.

Check Server Logs

Some errors won’t appear in WordPress logs.

Check:

  • Apache logs
  • Nginx logs
  • Hosting control panel

Common Fatal Errors

Example:

Call to a member function on null

Typical causes:

  • Plugin or theme conflict
  • Missing object initialization
  • PHP version incompatibility

Use Debugging Tools

Install:

  • Query Monitor

It provides insights into:

  • Slow database queries
  • PHP errors
  • Hooks and actions

Ensure Correct PHP Version

Recommended:

  • PHP 8.1 or higher

Older versions can break modern plugins and themes.

Effective debugging is about isolation.

Change one variable at a time and observe the results.

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