Written by Varun Dubey• May 7, 2025• 5:42 pm• Performance Optimization • Views: 14

Debugging WordPress Like a Pro: Tools and Techniques

Debugging WordPress is not just a skill—it’s a necessity. Whether you’re an individual developer, a freelancer, or part of an agency in India managing multiple client websites, the ability to detect, understand, and solve issues quickly is what sets professionals apart. This detailed guide explores practical techniques, essential tools, and real-world workflows to help you fix issues efficiently, reduce downtime, and deliver smoother user experiences.

Embracing the Debugging Mindset

The first step to becoming a pro debugger is adopting the right mindset. Don’t rush. Instead, observe the problem, reproduce it, isolate the root cause, solve it, and then prevent it from recurring.

This methodical approach not only saves time but also boosts the quality of your development. Debugging is not a sign of failure—it’s a sign of progress and learning.

Turning on WordPress Debug Mode

Edit your wp-config.php file to activate WordPress’s built-in debugging tools. Start with:

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

WP_DEBUG enables debugging mode.

WP_DEBUG_LOG stores errors in wp-content/debug.log.

WP_DEBUG_DISPLAY hides errors from frontend users.

SCRIPT_DEBUG forces WordPress to load unminified CSS and JS.

Always enable these settings in a development or staging environment—not on live sites.

Understanding the Core Debug Settings

Each debug constant plays a specific role:

WP_DEBUG_LOG: Logs errors and warnings to a file.

WP_DEBUG_DISPLAY: Controls whether these errors appear on screen.

SCRIPT_DEBUG: Ensures WordPress loads non-minified files—crucial for JS and CSS issues.

Combined, these provide full transparency into your WordPress environment.

Choosing the Right Local Development Environment

Your local environment should mirror your production server. Top tools include:

LocalWP and DevKinsta: GUI-based, user-friendly.
Docker: Ideal for developers needing control and replicability.
XAMPP or MAMP: Traditional stack setups.

Matching your local stack to production (PHP version, database type, etc.) ensures smoother debugging.

Isolating Issues in Themes and Plugins

If your site crashes or behaves strangely:

Switch to a default theme like Twenty Twenty-Four.
Deactivate all plugins.
Reactivate plugins one-by-one until the issue reappears.

Use tools like:

Health Check: Troubleshoots without affecting site visitors.
What The File: Identifies active template files quickly.

Logging HTTP Remote Connections

WordPress makes external HTTP calls using:

wp_remote_get(), wp_remote_post()

When APIs or webhooks fail:

Check response codes with wp_remote_retrieve_response_code()

Log issues with error_log()

Use plugins like: HTTP Requests Manager to view and control outgoing connections.

Profiling Code for Performance Insights

Not all bugs crash sites—some just slow them down.

Tools to identify performance issues:

Code Profiler: Visual load-time breakdowns.
Xdebug: PHP debugger with stack traces.
Tideways: Advanced performance monitoring.

These reveal memory hogs, long loops, and heavy queries.

Using Query Monitor and Debug Bar

Query Monitor: A must-have for inspecting:
- Database queries
- HTTP calls
- REST API
- PHP errors
Debug Bar: Adds debug menu to admin bar showing memory usage, templates, and request type.

Together, they offer real-time feedback on WordPress internals.

REST API and JavaScript Debugging

As WordPress becomes more JavaScript-heavy, debugging frontend scripts and REST APIs is essential:

Test APIs with:
- Postman
- Insomnia
Use browser DevTools to:
- View network requests
- Debug AJAX calls
- Fix console errors
Enable SCRIPT_DEBUG to get readable JS files.

Database Debugging and Cleanup

Slow or broken sites can stem from database clutter:

Use phpMyAdmin or Adminer to inspect:
- Orphaned meta rows
- Bloated wp_options
- Redundant transients
Advanced Database Cleaner: Cleans old revisions, auto drafts, and more.
WP-CLI: Automate database health checks and repairs.

Staging Environments: The Safe Zone

Never debug live. Instead, use staging environments like: Instawp or TasteWP

Manual cloning with All-in-One WP Migration or Duplicator

Staging sites allow you to test changes, log everything, and safely replicate live site behavior.

Real-World Debugging Examples

Here are a few examples of common debugging scenarios:

White screen of death after plugin install? Check debug.log.

API not working? Inspect HTTP headers, response codes, and payloads.

Slow site? Use Query Monitor and Code Profiler to trace slow hooks and queries.

AJAX not firing? Look at your JavaScript console and REST API routes.

Monitoring, Alerts, and Automation

Professional-grade debugging setups use:

Monitoring Tools:
- Uptime Robot
- Pingdom
Logging Platforms:
- Papertrail
- Loggly
Version Control & CI:
- GitHub Actions
- Bitbucket Pipelines
Static Analysis:
- PHPStan
- Psalm

These tools help detect and fix issues before they ever go live.

Final Thoughts

Debugging is more than solving bugs—it’s about understanding your stack, preventing future issues, and improving software quality. In India, where many agencies manage high-volume WordPress sites, these techniques are vital.

Here’s what separates pros from amateurs: