Mastering Debugging in WordPress: Tips for Smooth and Efficient Troubleshooting
12 min.

Encountered an issue on your WordPress site and need to fix it fast? Learn about debugging in WordPress, a crucial skill for identifying and solving problems swiftly. This guide will show you how to safely enable debug mode, interpret error messages, and use essential tools to get your site running smoothly again without overwhelming you with technical jargon.

Key Takeaways

  • Debugging in WordPress is facilitated through several built-in tools, such as WP_DEBUG, WP_DEBUG_LOG, and WP_DEBUG_DISPLAY, which help identify and log PHP errors without impacting the user experience when configured properly.

  • Editing the wp-config.php file is central to configuring various debug settings in WordPress, and using plugins like WP Debugging or Query Monitor can simplify the process and provide expanded debugging capabilities.

  • Best practices for WordPress debugging include using a staging site to avoid disrupting the live site, maintaining strong security practices while debugging, and utilizing advanced tools like Xdebug and hosting provider features for a thorough troubleshooting process.

Understanding WordPress Debug Mode

Debug Mode

WordPress debug mode is a powerful tool that helps to reveal PHP errors, notices, and warnings. As you navigate through the complex labyrinth of WordPress websites, you might find yourself in a situation where something just doesn’t work as expected. Perhaps you’ve installed a new plugin, configured a theme, or modified core files, only to find your website behaving strangely. Sounds familiar? That’s where enable WordPress debug mode comes in handy.

WordPress debug mode, once enabled, equips both developers and non-programmers with the ability to:

  • Identify and rectify errors related to WordPress themes, plugins, or custom codes using a WordPress debug plugin

  • Enhance your website’s security

  • Save you a ton of maintenance costs

  • Help understand various PHP errors such as minor notice errors, warning errors indicating potential issues, and critical parse errors caused by syntax problems, all of which can be found in the WordPress debug log.


Imagine having a magical switch that, when flipped, can reveal all the hidden issues lurking beneath your WordPress website. That’s pretty much what WP_DEBUG does. The debug mode in WordPress can be activated by using a PHP constant. This constant enables developers to troubleshoot and identify issues within the platform. To activate WP_DEBUG, one must edit the wp-config.php file on the server, setting the WP_DEBUG constant to true.

But what makes WP_DEBUG really special is its flexibility. It can be configured to either display all errors directly on your website or log them to a debug.log file without showing them to your site visitors. However, keep in mind that it’s necessary to disable WP_DEBUG once debugging is completed. Leaving it enabled could expose sensitive information, which is a risk you don’t want to take.

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While WP_DEBUG is the star of the show, its supporting actors, WP_DEBUG_LOG and WP_DEBUG_DISPLAY, play equally important roles in the WordPress debugging process. WP_DEBUG_LOG, for instance, enables error logging to a debug log file. This way, you can review and troubleshoot errors without affecting your site’s user experience. Its utilization may require the creation of a debug.log file in the wp-content directory and modifications to the file permissions to accommodate error recording.

On the other hand, WP_DEBUG_DISPLAY determines if error messages should be shown directly on the webpage. By default, this option is set to true, showcasing errors in the HTML output. However, setting WP_DEBUG_DISPLAY to false is recommended for security purposes and to enhance user experience. This prevents errors from being displayed to end users, while you can still use WP_DEBUG_LOG to record those errors for developers.

Setting Up WordPress Debugging

WordPress Debugging

With a clear understanding of the roles of WP_DEBUG, WP_DEBUG_LOG, and WP_DEBUG_DISPLAY, it’s time to explore how to set up WordPress debugging. By enabling WP_DEBUG, you allow for thorough troubleshooting by displaying all PHP errors, notices, and warnings. But what is the exact method to activate it?

The process involves adding specific lines to the wp-config.php file. To manually enable debug mode, edit the wp-config.php file and insert the appropriate lines of code. And to disable it, simply remove or update the relevant settings within the file. Remember, while WordPress debug logs should not be edited directly, they serve as a valuable reference for identifying and addressing problems on your site.

Editing wp-config.php

The wp-config.php file is the heart of your WordPress website’s configuration, also known as wp config. It’s where you can define a host of settings, including enabling or disabling WP_DEBUG. This file can be modified using a File Manager or File Transfer Protocol (FTP) clients such as FileZilla. The process involves accessing the file via an FTP client or your hosting cPanel, making the desired changes, and then uploading it back to the server.

Here’s a pro tip: when making alterations for WP_DEBUG and other constants, ensure you place the code in the wp-config.php file before the line that reads ‘/ That’s all, stop editing! Happy blogging. /‘. To log errors without showing them on your website, set WP_DEBUG_DISPLAY to false and add the code ‘@ini_set(‘display_errors’, 0)’ to the wp-config.php file.

Enabling Additional Debug Options

While WP_DEBUG, WP_DEBUG_LOG, and WP_DEBUG_DISPLAY play key roles in WordPress debugging, the platform also offers extra debug options to enhance debugging capabilities. One such option is SCRIPT_DEBUG. When enabled, it forces WordPress to use the non-minified, more readable, and commented ‘dev’ versions of core CSS and JS files. This comes in handy when debugging JavaScript and CSS issues.

Another beneficial feature is SAVEQUERIES. This feature saves every database query to an array, allowing for in-depth analysis and troubleshooting. However, it’s important to disable this feature when not in use to avoid performance degradation. Activating these additional debug options involves appending specific lines of code to the wp-config.php file.

Utilizing Plugins for Efficient WordPress Debugging

WordPress Debugging

In the WordPress universe, plugins often come to the rescue. When it comes to debugging, the WP Debugging wordpress plugin can make your life significantly easier. This plugin enables debug mode without the need for manual file editing, making it ideal for streamlining the configuration process of debugging. To enable WordPress debug, simply activate the plugin by installing and enabling it from the WordPress admin dashboard, where you can set ‘Set WP_DEBUG to true’ to commence debugging.

Don’t forget to disable the WP Debugging plugin once debugging is completed. You can do this by following these steps:

  1. Go to the WordPress plugins page.

  2. Find the WP Debugging plugin and click on the “Deactivate” link.

  3. Check for any additional clean-up options on the plugin settings page and make sure to disable them as well.

Advanced plugin features offered by hosting providers can include:

  • Viewing and clearing error logs from the WordPress admin area

  • Downloading backups of critical files

  • Sending fatal errors to communication platforms for real-time monitoring.

Query Monitor: A Comprehensive Debug Tool

Among the myriad of WordPress debugging plugins, Query Monitor stands tall as a comprehensive debug tool. The plugin offers comprehensive debugging features for different areas of WordPress. These include database queries, PHP errors, hooks and actions, block editor blocks, enqueued scripts and stylesheets, and HTTP API calls. It also offers further debugging tools for Ajax calls and REST API calls, and supports block themes in full site editing context.

Query Monitor offers the following features:

  • User-friendly interface that allows users to categorize and filter database queries by type, the component they originate from, and the calling function, simplifying the analysis of database interactions.

  • Admin toolbar menu that provides an overview of debugging data for the current page, with comprehensive details available upon selection.

  • Respects user privacy by operating without saving data persistently or sharing it with third parties.

Debug Bar and Other Helpful Plugins

While Query Monitor is an excellent tool for WordPress debugging, it’s not the only plugin that can streamline the process. Enter Debug Bar, a plugin that adds a menu to the admin bar, providing a centralized location where error logs, cache, and queries related to debugging can be easily accessed. Additionally, Debug Bar supports multiple add-ons, each offering enhanced functionality for debugging different aspects of WordPress.

Beyond Debug Bar, there are other useful plugins like WP Crontrol and WP Debugging. WP Crontrol allows for the inspection and management of WP-Cron events, while WP Debugging provides tools for configuring error reporting and logging. Debugging information like logs can be viewed and cleared through the Debug Bar plugin within the WordPress backend, and Debug Bar add-ons can be accessed via Query Monitor, highlighting the interconnectivity of these tools.

Best Practices for Safely Debugging Your WordPress Site

Practices for Safely Debugging

As with any development process, debugging in WordPress requires a certain level of caution to ensure your website’s functionality and user experience remain unaffected. This is why adhering to best practices is paramount. One of these best practices is using WordPress staging tools or plugins to set up a controlled testing environment. This allows you to debug safely without affecting the live site’s user experience.

Before making any changes for debugging, it’s advisable to always backup the wp-config.php file. This can be achieved with the help of plugins that offer backup features and debugging tools. To ensure continued site security and performance, disable WP_DEBUG, WP_DEBUG_DISPLAY, and WP_DEBUG_LOG post-debugging and only enable WPDB error reporting within the safety of a staging environment.

Also, consider incorporating version control tools like Git during the debugging process and remember to switch off maintenance mode after debugging to make the site accessible to visitors again.

Conducting Debugging on a Staging Site

Debugging on a staging site comes with a host of advantages. A staging site provides a controlled environment to test and fix code before pushing changes to the live website, preventing impact on user experience. Debugging on a staging site allows for troubleshooting without risking the functionality or appearance of the live website.

Staging sites offer several benefits:

  • They are independent from the live site, allowing for safe testing without affecting the live environment.

  • Changes made in the staging site do not affect the live site, ensuring that debugging can be conducted without exposing the live site to errors or security vulnerabilities.

  • When creating a staging site, sensitive data such as API keys and database data are cloned, requiring careful management to avoid security risks.

Security Considerations While Debugging

Though debugging is vital for the upkeep and enhancement of your WordPress website, it remains essential to bear security considerations in mind. For instance, to enable debugging, set WP_DEBUG_LOG to true, which will write errors to a special log file without displaying them on the live site. Furthermore, toggle WP_DEBUG_DISPLAY to false to ensure error messages are not shown to site visitors while debugging.

It’s also beneficial to utilize maintenance mode during debugging to prevent errors from being visible to visitors and to maintain the site’s professional appearance. Additionally, restrict Query Monitor output to Administrators or Super Admins in single or multi-site installations respectively. Implement an authentication cookie to selectively allow visibility of Query Monitor output for non-logged in users or non-Administrators.

Finally, conduct debugging in a staging environment, enabling WPDB error reporting only in this secured environment to mitigate security risks.

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Resolving Common Debugging Issues

During your debugging journey in WordPress, you are likely to come across some common issues. But fear not! There are tried-and-tested strategies for resolving these issues. Here are some common types of errors and their causes:

  1. Startup errors: These typically relate to installation issues.

  2. Compile-time errors: These occur when there are undefined functions or data.

  3. Runtime errors: These occur during the execution phase.

Identifying the timing of an error’s occurrence can help pinpoint its cause.

Enabling WPDB error reporting in WordPress is useful for detecting and diagnosing errors in database operations. It can help identify issues like syntax errors and database connection problems. To fix a 404 error in WordPress, you can refresh the page, check the URL for mistakes, and repair any broken links that may have caused the error. And don’t forget that server logs provide valuable information for identifying the source of various WordPress issues, including slow website performance, malfunctioning plugins, and causes of website crashes.

Dealing with Error Messages

Debugging inherently involves dealing with error messages. They are the clues that guide you to the underlying issue. When WP_DEBUG is enabled, deprecated functions and arguments are highlighted, indicating functions that will be removed in the future and suggesting alternatives. Warning errors alert developers to issues such as:

  • non-existent file paths, prompting verification and correction of file names

  • incorrect syntax or missing semicolons in code

  • undefined variables or functions

  • database connection errors

These error messages help identify and fix issues in your code.

PHP warning messages can relate to:

  • File permission issues, indicating the server’s inability to access a PHP file due to incorrect permissions

  • Security issues such as server connections closed due to harmful threats like malicious bots

  • Parse errors requiring syntax correction in the PHP code, such as fixing invalid variables, unclosed quotations, and punctuation errors

Error messages generated in WordPress are stored in the debug log file within the /wp-content/ directory, accessible via SFTP/FTP or file manager tools. To better understand this process, let’s log file define as a record of events or errors that occur within a software program.

Debugging JavaScript Files and Other Assets

Debugging extends beyond just addressing PHP errors. JavaScript files and other assets can also present challenges. Browser development tools, such as Chrome DevTools, offer a suite of utilities like the JavaScript debugger, which can be used to set breakpoints and step through code execution.

Monitoring network requests in browser developer tools can help identify failed asset loadings, such as 404 errors for missing JavaScript files. Checking for JavaScript errors using the browser’s console is a quick way to find syntax errors or issues with external libraries that may not be loading correctly.

Use of version control systems like Git can help track changes in JavaScript files, css files, and other assets to pinpoint when an issue was introduced and facilitate debugging.

Advanced Debugging Tools and Strategies

Debugging Tools

While the previously discussed tools and strategies cater to most debugging requirements, advanced techniques are available to elevate your debugging skills further. For instance, advanced WordPress developers can use Chrome DevTools for client-side debugging. Using SSH to access the server terminal can provide powerful command-line tools for real-time debugging.

Some tools that can enhance traditional PHP debugging are:

  • Xdebug, which provides breakpoints, stack traces, and profiling

  • Local by Flywheel, which offers a local debugging environment for WordPress, including SSL support and easy log access

  • WP-CLI, which can speed up debugging tasks like plugin and theme management

  • PHPStorm, a dedicated IDE that can connect with Xdebug for an integrated, advanced debugging experience.

Leveraging Server Logs and Hosting Provider Tools

Server logs, coupled with hosting provider tools, can provide improved debugging insights and capabilities. Error logs in WordPress provide a detailed list of error messages with their occurrence dates and times, which are crucial for pinpointing issues in plugins, themes, or custom code during debugging. Server logs can help identify and troubleshoot common WordPress errors such as:

  • The white screen of death

  • PHP errors

  • Invalid JSON errors

  • Access permission issues

Advanced hosting tools enhance debugging by providing features like regex playgrounds with cheat sheets, options to modify WP heartbeat settings, and extensions of cURL timeout settings. Some hosting providers offer plugins and tools that enable developers to interact with functions.php, monitor wp_mail() failures, and edit user and post meta directly from the admin panel, as well as manage PHP settings and scheduled cron jobs.

Embracing New Technologies for Debugging

As technology progressively evolves, so do the tools and strategies associated with debugging. One such emerging technology is ChatGPT. It can be harnessed to write and debug code within WordPress, supporting various languages including CSS, HTML, and PHP. When integrated via WordPress plugins, such as Divi AI and AI Engine, ChatGPT aids in code creation and streamlines problem-solving, proving its value beyond just content generation.

By leveraging ChatGPT, ProCoders enhances debugging workflows and troubleshoots issues more efficiently, reflecting their commitment to using innovative technology solutions. Indeed, innovation is at the heart of ProCoders’ commitment, as they strive to deliver comprehensive full-cycle development services that push the boundaries of technology.


Mastering WordPress debugging is not a task for the faint-hearted. It requires a deep understanding of various tools and strategies, from enabling WP_DEBUG and leveraging server logs to utilizing advanced plugins and embracing new technologies like ChatGPT. However, with the right approach, you can transform WordPress debugging from a daunting task into an opportunity to enhance your website’s security, reduce maintenance costs, and streamline the process of identifying and fixing errors. Remember, every error is a learning opportunity, and every workaround, a step towards becoming a master of WordPress debugging.

How do I enable debugging in WordPress?

To enable debugging in WordPress, open the wp-config.php file and set the WP_DEBUG constant to true. This will allow you to troubleshoot any issues with your website.

What is the plugin for debugging WordPress?

The plugin for debugging WordPress can be easily installed and activated through plugins in the WordPress dashboard. Popular options include WP Debugging and Query Monitor, which streamline the process and provide detailed error logs.

What is the purpose of WordPress debug mode?

The purpose of WordPress debug mode is to reveal PHP errors, notices, and warnings, which helps in identifying problems in WordPress websites after changes. It plays a critical role in maintaining website functionality.

How can I resolve common debugging issues in WordPress?

To resolve common debugging issues in WordPress, enable WPDB error reporting, refresh the page, and repair any broken links that may have caused the error. Server logs also offer valuable information for identifying various WordPress issues.

What are some advanced debugging tools and strategies?

Consider using Chrome DevTools for client-side debugging, SSH for server access, server logs, and hosting provider tools, as well as exploring new technologies like ChatGPT. These advanced tools and strategies can significantly enhance your debugging process.

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