The Ultimate Guide To WordPress Debugging Tools And Techniques

The Ultimate Guide To WordPress Debugging Tools And Techniques

May 25, 2023

In a perfect world, your WordPress site would run flawlessly without any issues. However, in reality, you will undoubtedly encounter problems that require debugging. WordPress offers a built-in debug mode and a variety of third-party tools to help you diagnose and resolve these issues. This ultimate guide will walk you through various debugging tools and techniques to keep your WordPress site running smoothly and efficiently.

Key Takeaways

  • WordPress debugging is essential for identifying and resolving errors on your website.

  • Enabling WP_DEBUG mode is a fundamental step in diagnosing WordPress issues.

  • Browser developer tools are invaluable for front-end debugging, including inspecting elements and analyzing network requests.

  • There are several popular debugging plugins like Query Monitor and Debug Bar that can simplify the debugging process.

  • Securing your debugging process is crucial to prevent exposure of sensitive information and ensure a safe debugging environment.

Enabling WP_DEBUG Mode

Enabling WP_DEBUG mode is a crucial first step in troubleshooting WordPress issues. This built-in debugging tool helps you identify and resolve errors, notices, and warnings on your website.

How to Enable WP_DEBUG

To enable WP_DEBUG, follow these steps:

  1. Access your WordPress site’s files through an FTP client or file manager.

  2. Locate the wp-config.php file, usually found within the public folder.

  3. Open the wp-config.php file in a text editor.

  4. Look for the line that says define('WP_DEBUG', false); and change false to true.

  5. Save the changes and upload the modified wp-config.php file back to the server.


While WP_DEBUG is informative, it can clutter your website’s frontend with debugging information. To tackle this, WordPress provides two additional tools – WP_DEBUG_LOG and WP_DEBUG_DISPLAY.

  • WP_DEBUG_LOG: This logs all errors to a debug.log file located in the /wp-content/ directory. Enable it by adding define('WP_DEBUG_LOG', true); to your wp-config.php file.

  • WP_DEBUG_DISPLAY: This controls whether debugging messages are shown inside the HTML of your pages. Disable it by adding define('WP_DEBUG_DISPLAY', false); and @ini_set('display_errors', 0); to your wp-config.php file.

Common Issues Detected by WP_DEBUG

WP_DEBUG can help you identify a variety of issues, including:

  • Deprecated functions and arguments

  • Database connection errors

  • Plugin and theme conflicts

Enabling debugging in WordPress is a first troubleshooting step. Once you’re finished, you can either set the constants to false or just remove the snippet to disable debug mode.

Using Browser Developer Tools

Browser developer tools can be invaluable when it comes to debugging WordPress sites. They provide insights into the behavior of your site, allowing you to monitor network requests, inspect HTML and CSS, view console logs, and more.

Popular Debugging Plugins

When it comes to debugging WordPress, several plugins can make the process significantly easier and more efficient. Below are some of the most popular debugging plugins that you should consider adding to your toolkit.

Query Monitor

Query Monitor is an essential plugin for developers who need to understand what’s happening behind the scenes. It provides detailed information about database queries, hooks, and more. This plugin allows you to troubleshoot database queries and PHP errors effectively. Additionally, it supports integration with other plugins like the Debug Bar, adding more functionality for debugging and troubleshooting.

Debug Bar

Debug Bar adds a debugging menu to the admin bar in WordPress, making it easy to debug individual pages rapidly. The plugin adds a troubleshooting menu for checking query, cache, warnings, and debugging. This makes it much easier to identify problems on a page. You can conveniently create, view, filter, and clear the debug.log file.

Log Deprecated Notices

Log Deprecated Notices is another useful plugin that helps you keep track of deprecated functions and files in your WordPress installation. This can be particularly useful for developers maintaining older sites or plugins. The plugin logs these notices, allowing you to update or replace deprecated code efficiently.

Using these plugins can significantly streamline your debugging process, making it easier to identify and resolve issues quickly.

Troubleshooting Common WordPress Errors

Before we dive into the specifics of debugging, it’s important to understand some of the most common errors that can occur on a WordPress website. Some of the most common errors include the White Screen of Death, Internal Server Errors, and Plugin and Theme Conflicts. Diagnosing these errors can be the first step towards resolving them effectively.

To diagnose these errors, you can start by checking the error logs in your server or in the WordPress debug.log file, if you have enabled debugging. Additionally, you can use debugging tools such as Query Monitor or Debug Bar to help identify the source of the problem.

Securing Your Debugging Process

While debugging is essential for maintaining a healthy WordPress site, it’s crucial to prioritize security. Debugging can potentially expose sensitive information, such as database credentials or file paths, if not handled properly.

Hiding Sensitive Information

Avoid including sensitive information, such as passwords or API keys, in your debugging code. Any hardcoded credentials used for testing purposes should be removed or obfuscated before deploying your website to a live environment.

Using Secure Connections

Ensure that you are using secure connections (HTTPS) when debugging your WordPress site. This helps protect the data transmitted between your browser and the server, reducing the risk of interception by malicious actors.

Best Practices for Debugging in Production

  1. Limit access to debugging tools and logs to authorized personnel only.

  2. Regularly review and clean up plugin logs and other debugging files to prevent unauthorized access.

  3. Use environment-specific configurations to enable debugging only in development or staging environments, not in production.

Following these precautions will help protect your website and ensure that debugging remains a helpful and secure process.

Advanced Debugging Techniques

In this section, you’ll be introduced to more advanced techniques, such as performance profiling, memory leak detection, and debugging in a distributed system environment. It’s essential to understand your code’s flow and identify bottlenecks. Specific tools help you visualize the code execution, making it easier to find where things are going wrong.

Optimizing Your WordPress Site

Optimizing your WordPress site is crucial for ensuring fast load times, a smooth user experience, and better search engine rankings. Here are some key techniques and tools to help you achieve optimal performance.

Performance Monitoring Tools

To keep your site running smoothly, it’s essential to monitor its performance regularly. Using performance monitoring tools can help you identify bottlenecks and areas for improvement. Some popular tools include:

  • Google PageSpeed Insights

  • GTmetrix

  • Pingdom

These tools provide detailed reports on various performance metrics, helping you make informed decisions about optimizations.

Caching Strategies

Implementing effective caching strategies can significantly reduce load times and server strain. Consider using the following caching methods:

  1. Browser Caching: Stores static files in the user’s browser, reducing the need to re-download them on subsequent visits.

  2. Server-Side Caching: Utilizes plugins like W3 Total Cache or WP Super Cache to store dynamic content as static files.

  3. Content Delivery Network (CDN): Distributes your site’s content across multiple servers worldwide, ensuring faster delivery to users based on their geographic location.

Database Optimization Tips

A well-optimized database is essential for maintaining your site’s performance. Regularly clean up and optimize your database by:

  • Removing unnecessary data such as post revisions, spam comments, and trashed items.

  • Using plugins like WP-Optimize or WP-Sweep to automate the cleanup process.

  • Ensuring your database tables are properly indexed to speed up query execution.

Keeping your WordPress version, plugins, and themes up-to-date is vital for both performance and security. Regular updates ensure you have the latest features and security patches.

By following these tips and utilizing the right tools, you can significantly improve your WordPress site’s performance and provide a better experience for your visitors.


Debugging is an indispensable skill for anyone managing a WordPress site. This guide has walked you through various tools and techniques, from enabling WP_DEBUG to using third-party plugins and browser developer tools. By mastering these debugging methods, you can quickly diagnose and resolve issues, ensuring your website remains secure, optimized, and high-performing. Remember, a well-debugged site not only runs smoothly but also offers a better user experience and improved search engine rankings. Keep these best practices in mind, and you’ll be well-equipped to handle any WordPress-related challenges that come your way.

Frequently Asked Questions

What is WP_DEBUG in WordPress?

WP_DEBUG is a built-in constant in WordPress that helps developers identify and fix issues by displaying PHP errors and warnings. Enabling WP_DEBUG is essential for troubleshooting issues on your site.

How do I enable WP_DEBUG mode?

To enable WP_DEBUG mode, add the following line to your wp-config.php file: define(‘WP_DEBUG’, true);. This will activate the debug mode and display errors and warnings on your site.

What are some common issues detected by WP_DEBUG?

WP_DEBUG can help detect various issues such as deprecated functions, PHP errors and warnings, and issues with theme or plugin code. It’s a valuable tool for identifying problems that may affect your site’s performance and functionality.

Which browser developer tools are useful for WordPress debugging?

Browser developer tools like Chrome DevTools, Firefox Developer Tools, and Safari Web Inspector are essential for inspecting elements, debugging JavaScript, and analyzing network requests. These tools help you identify and fix front-end issues on your WordPress site.

What are some popular WordPress debugging plugins?

Popular WordPress debugging plugins include Query Monitor, Debug Bar, and Log Deprecated Notices. These plugins provide detailed insights into your site’s performance, database queries, and deprecated functions, making it easier to troubleshoot issues.

How can I secure my debugging process in WordPress?

To secure your debugging process, ensure that you hide sensitive information by disabling WP_DEBUG_DISPLAY and using WP_DEBUG_LOG to log errors to a file. Additionally, use secure connections (HTTPS) and follow best practices for debugging in production environments to prevent exposing sensitive data.

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