WP Debugging


This plugin sets the following debug constants in wp-config.php on plugin activation and removes them on plugin deactivation. Any errors will result in a PHP Exception being thrown. Debug constants per Debugging in WordPress.

Default settings:

define( 'WP_DEBUG_LOG', true );
define( 'SCRIPT_DEBUG', true );
define( 'SAVEQUERIES', true );

@ini_set( ‘display_errors’, 1 ); is set when the plugin is active. WP_DEBUG is set to true when the plugin is first run, thereafter it can be turned off in the Settings.

The Settings page allows the user to set the following.

define( 'WP_DEBUG', true ); // Default on initial plugin installation.
define( 'WP_DEBUG_DISPLAY', false ); // Default when not declared is true.
define( 'WP_DISABLE_FATAL_ERROR_HANDLER', true ); // WordPress 5.2 WSOD Override.

When the plugin is deactivated best efforts are made to re-add pre-existing constants to their former state. When the plugin is activated the default settings and any saved settings are restored.

This plugin uses the wp-cli/wp-config-transformer command for writing constants to wp-config.php.

Debug Quick Look from Andrew Norcross is included with this plugin to assist in reading the debug.log file. If you already have this plugin installed you should delete it when WP Debugging is not active.

Query Monitor and Debug Bar plugins are optional dependencies to aid in debugging and troubleshooting. The notice for installation will recur 45 days after being dismissed.

If you have a non-standard location for your wp-config.php file you can use the filter wp_debugging_config_path to return the file path for your installation.

The filter wp_debugging_add_constants allows the user to add constants to wp-config.php.

The filter returns an array where the key is the name of the constant and the value is an array of data containing the value as a string and a boolean to indicate whether or not the value should be passed without quotes.

$my_constants = [
    'my_test_constant' =>
        'value' => 'abc123',
        'raw' => false,
    'another_test_constant' => [ 'value' => 'true' ],

The value option contains the constant’s value as a string.

The raw option means that instead of placing the value inside the config as a string it will become unquoted. The default is true. Set as false for non-boolean values.


    function( $added_constants ) {
        $my_constants = [
            'my_test_constant'      => [
                'value' => '124xyz',
                'raw'   => false,
            'another_test_constant' => [ 'value' => 'true' ],
        return array_merge( $added_constants, $my_constants );

This will create the following constants.

define( 'MY_TEST_CONSTANT', '124xyz' );
define( 'ANOTHER_TEST_CONSTANT', true );


PRs are welcome against the develop branch on GitHub.


  • Settings Screen


November 15, 2019
Thanks for the useful plugin, we're going to start recommending this to our customers.
May 13, 2019
I can't tell you the number of times I've had to handle a support request that involved a white screen. Thank you, @afragen, for building this awesome tool to help define constants for a file that isn't easily accessible without passing around credentials.
May 3, 2019
This helps me support customers and get better debugging information about errors happening on their site without having to ask for sensitive login info. Simple and does a great job, I've used it or recommended it a dozen times in the last month.
March 21, 2019
I work in customer support and am pretty consistently needing to check error logs. This creates a lot of back-and-forth with customers. This plugin has severely cut down on that back-and-forth as I can now enable debug.log within the WP Dashboard and I can view the log right there as well. Highly recommend this plugin!
Read all 5 reviews

Contributors & Developers

“WP Debugging” is open source software. The following people have contributed to this plugin.


Translate “WP Debugging” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.


2.9.0 / 2020-08-15

  • use try/catch around use of WPConfigTransformer object

2.8.0 / 2020-08-01

  • exit if called directly
  • NB: I have seen the WPConfigTransformer Exception error live. The issue seems to be that a file_get_contents() on the wp-config.php file path, at random times, returns an empty value. I’m done chasing this random error in wp-cli/wp-config-transformer. Modified version of wp-cli/wp-config-transformer present

2.7.2 / 2020-06-01

  • test wp-config.php everywhere, still occasional WSOD reports.

2.7.1 / 2020-5-15

  • return early if wp-config.php is empty before calling WPConfigTransformer

2.7.0 / 2020-04-30

  • start loading in init hook
  • run process_filter_constants() as chained method in Bootstrap

2.6.1 / 2020-03-28

  • move Settings action link to front
  • change test for wp-config.php file empty

2.6.0 / 2020-02-28

  • load autoloader in main file
  • update composer dependencies

2.5.8 / 2019-12-23

  • badly messed up check for empty wp-config.php

2.5.7 / 2019-12-20

  • check and exit early if wp-config.php is empty
  • return empty array for the above exit

2.5.6 / 2019-11-02

  • early exit if wp-config.php not set in specific functions

2.5.5 / 2019-09-17

  • update composer.json for wp-dependency-installer update, now requires at least PHP 5.6 for spread operator
  • composer update

2.5.4 / 2019-04-25

  • added check for writable wp-config.php, exit with notice if not found

2.5.3 / 2019-04-01

  • update Debug Quick Look to display error log file path

2.5.1 / 2019-04-01

  • updated version of wp-cli/wp-config-transformer

2.5.0 / 2019-03-25

  • added wp_debugging_add_constants filter for users to add their own constants

2.4.3 / 2019-03-09

  • missed an output escape

2.4.2 / 2019-02-26

  • add Domain Path header

2.4.1 / 2019-02-10

  • refactor set/restore pre-activation constants

2.4.0 / 2019-02-06

  • save pre-activation constants for re-installation on deactivation ( say that 5x fast )

2.3.0 / 2019-02-04

  • look for wp-config.php in directory above ABSPATH
  • add filter wp_debugging_config_path to set non-standard path to wp-config.php

2.2.0 / 2019-02-02 🏈

  • initial release on dot org

2.1.1 / 2019-02-01

  • only show WSOD bypass when appropriate
  • update dependencies

2.1.0 / 2019-01-26

  • update Debug Quick Look, minor CSS changes
  • Improve messaging
  • add setting for WP_DISABLE_FATAL_ERROR_HANDLER constant (WSOD)
  • add default setting of WP_DEBUG to true, can be changed

2.0.0 / 2019-01-18

  • total re-write
  • add settings page
  • use wp-cli/wp-config-transformer to change wp-config.php
  • include norcross/debug-quick-look as dependency via composer but use my fork
  • update POT via composer.json and wp-cli
  • add image assets