Senior WordPress Developer Interview Questions with Answers

What are the most important hooks in WordPress and how do you use them?
- Hooks allow you to modify default WordPress behavior. Actions (add_action) let you add custom functionality at specific points, and filters (add_filter) let you modify data before it's displayed.
Explain the WordPress template hierarchy.
- WordPress uses a specific order to choose templates for different pages, e.g., single.php for single posts, archive.php for archives, and page.php for static pages.
What is the difference between get_option() and get_site_option()?
- get_option() retrieves site-specific options, while get_site_option() retrieves multisite options across the network.
How do you create a custom WordPress theme or plugin?
- For a theme, create a folder in wp-content/themes, with a style.css and index.php file. For a plugin, create a folder in wp-content/plugins with a main PHP file.
How do you create a custom post type (CPT) and taxonomy?
- Use register_post_type() for CPTs and register_taxonomy() for custom taxonomies in your theme or plugin.
What are WordPress shortcodes?
- Shortcodes are snippets of code enclosed in square brackets, like [shortcode], that allow users to insert dynamic content easily.

How do you handle responsive design in WordPress themes?
- Use CSS media queries and flexible grid systems like Bootstrap to ensure your theme adjusts to various screen sizes.
How would you integrate a JavaScript framework (React, Vue.js, etc.) into WordPress?
- Enqueue the JavaScript files using wp_enqueue_script() and ensure the front-end interacts with WordPress through REST API or AJAX.
What CSS preprocessors have you used, and why would you use them in a WordPress project?
- SASS/SCSS is commonly used to organize CSS into reusable components and manage complex styling more efficiently.
How would you optimize the WordPress database?
- Remove unused data, use database indexing, and optimize queries. Use plugins like WP-Optimize for cleanup.
Explain how WordPress handles database queries.
- WordPress uses $wpdb for secure database queries, allowing interaction with the database while preventing SQL injection.
Describe how to work with REST APIs in WordPress.
- Use wp-json endpoints to interact with WordPress data from external applications. You can create custom REST API endpoints using register_rest_route().

How do you use Git in your WordPress development process?
- I use Git for version control to track changes, create branches for features, and collaborate using GitHub or GitLab for pull requests and code reviews.
What is your approach to deploying a WordPress site to production?
- Use a staging environment, ensure proper backups, and deploy via FTP, SSH, or CI/CD pipelines like GitHub Actions or Bitbucket Pipelines.

How do you debug a WordPress site?
- I enable WP_DEBUG and WP_DEBUG_LOG in the wp-config.php file, then use the error_log() function to trace errors.
How would you troubleshoot plugin/theme compatibility issues?
- Deactivate all plugins, switch to the default theme, and reactivate them one by one to identify conflicts.

What coding standards do you follow when developing WordPress themes and plugins?
- I follow the WordPress Coding Standards for PHP, HTML, CSS, and JavaScript to maintain clean, readable, and consistent code.
How do you ensure that your code is maintainable?
- I write modular code, use proper comments, adhere to coding standards, and ensure all functions and classes are reusable.

How do you collaborate with non-technical clients or stakeholders?
- I simplify technical concepts, provide visual prototypes, and use plain language to explain the development process and challenges.

How would you approach building a custom admin dashboard in WordPress?
- I would use the add_menu_page() and add_submenu_page() functions to create custom dashboard pages and display relevant data through WordPress options or custom queries.
How would you optimize a WordPress site for scalability?
- Use a Content Delivery Network (CDN), implement caching strategies, and optimize database queries and file sizes.

Tell us about the most complex WordPress project you’ve worked on.
- Describe a challenging project, your role, the technologies used, the problems faced, and how you resolved them.

How do you prioritize tasks when working with tight deadlines?
- I focus on high-impact tasks first, break them down into smaller chunks, and use project management tools like Trello or Asana for tracking.