Show a practical setup: "WP_DEBUG and WP_DEBUG_LOG on in development. Query Monitor for database and hook debugging. Xdebug with VS Code for stepping through complex issues. WP-CLI for database and plugin management."
Debugging: WP_DEBUG, WP_DEBUG_LOG, WP_DEBUG_DISPLAY constants in wp-config.php. Query Monitor plugin for database queries, hooks, HTTP requests, and PHP errors. Xdebug for step-through debugging. error_log() for quick logging. Local development: LocalWP (easiest), Docker with WordPress image, DAMP/LAMP stack, or wp-env (official). Strong candidates mention: SAVEQUERIES constant for query logging, wp-cli for command-line operations, browser DevTools for frontend debugging, and Health Check plugin for troubleshooting without affecting other users.
Baseline professional WordPress development. Candidates who debug by adding var_dump and refreshing are missing essential tools. Those who know Query Monitor, Xdebug, and WP-CLI have a professional debugging workflow.