WordPress Beginner Interview Questions

General WordPress Basics

1. What is WordPress?

WordPress is a Content Management System (CMS) written in PHP that uses a MySQL or MariaDB database. It helps users create and manage websites without needing to write code.

Features:

• Free and open source under GPL
• Highly customizable using plugins and themes
• Supports blogs, ecommerce, portfolios, forums, and more

How it works:

1. A visitor requests a page.
2. WordPress loads PHP files.
3. Connects to the database and fetches the required content.
4. Combines content with theme templates.
5. Sends the generated HTML to the browser.

2. What are the key differences between WordPress.org and WordPress.com?

• Use WordPress.org if you want full control.
• Use WordPress.com for convenience and simplicity.

3. How do you install WordPress locally?

Steps using XAMPP:

1. Install XAMPP and start Apache + MySQL.
2. Download WordPress from wordpress.org.
3. Extract it to htdocs/my-site inside XAMPP directory.
4. Open http://localhost/phpmyadmin and create a database (my_site_db).
5. Visit http://localhost/my-site and follow the installation wizard.

4. What is the wp-content directory used for?

wp-content/ holds all the custom content added to your site.

Main subfolders:

• themes/ – Your site’s design files.
• plugins/ – Functionality extensions.
• uploads/ – Media files (images, videos, PDFs).

Why it matters:

• This folder is where 90% of customization lives.
• When migrating a site, this is the most important folder to back up.

5. What is a plugin in WordPress?

A plugin is a package of PHP code that extends or adds functionality to WordPress.

Example: Simple Login Logger Plugin

<?php
/*
Plugin Name: Login Logger
*/

function my_login_logger($user_login, $user) {
    error_log("User '{$user_login}' logged in at " . current_time('mysql'));
}
add_action('wp_login', 'my_login_logger', 10, 2);

How to install:

• Upload to wp-content/plugins/
• Activate via Dashboard > Plugins

6. What is a WordPress theme?

A theme defines the visual design of a WordPress site. It controls layout, styles, and templates.

Basic Theme Files:

• style.css – Required stylesheet with theme info.
• index.php – Fallback template.
• functions.php – Theme configuration.

Example: style.css

/*
Theme Name: My Theme
Author: You
Version: 1.0
*/

7. What does the wp-config.php file do?

This file sets important configuration settings, including:

Example:

define('DB_NAME', 'my_database');
define('DB_USER', 'root');
define('DB_PASSWORD', '');
define('DB_HOST', 'localhost');
define('WP_DEBUG', true);
$table_prefix = 'wp_';

You should not expose or modify this file carelessly as it contains sensitive data.

8. How do you update WordPress to the latest version?

Method 1: Dashboard

• Go to Dashboard > Updates
• Click “Update Now”

Method 2: WP-CLI

wp core update

Precautions:

• Back up your site.
• Check theme/plugin compatibility.
• Avoid updates on live site during high traffic.

9. What is the admin dashboard?

The admin dashboard is the backend interface where site owners manage the site. Accessible via:

https://yoursite.com/wp-admin

Core Sections:

• Posts, Pages, Media
• Appearance
• Plugins
• Settings
• Tools

Add a custom dashboard widget:

function my_dashboard_widget() {
    echo "Welcome to your custom dashboard!";
}

function register_my_dashboard_widget() {
    wp_add_dashboard_widget('my_widget', 'My Widget', 'my_dashboard_widget');
}
add_action('wp_dashboard_setup', 'register_my_dashboard_widget');

10. What is a widget in WordPress?

Widgets are modular content blocks placed in sidebars, footers, or other widget areas.

Classic Widgets:

• Go to Appearance > Widgets
• Drag and drop widgets like “Search” or “Recent Posts”

Create a custom widget (basic version):

class My_Custom_Widget extends WP_Widget {
    public function __construct() {
        parent::__construct('my_custom_widget', 'My Custom Widget');
    }

    public function widget($args, $instance) {
        echo $args['before_widget'] . 'Hello from my custom widget!' . $args['after_widget'];
    }
}

function register_my_custom_widget() {
    register_widget('My_Custom_Widget');
}
add_action('widgets_init', 'register_my_custom_widget');

11. What is a shortcode?

Shortcodes are placeholders for dynamic content. They look like [my_shortcode].

Define a shortcode using a named function:

function my_hello_shortcode() {
    return 'Hello, this is a shortcode!';
}
add_shortcode('my_shortcode', 'my_hello_shortcode');

Use in content:

[my_shortcode]

WordPress will output: Hello, this is a shortcode!

12. How do you create a page in WordPress?

Steps:

1. Dashboard > Pages > Add New
2. Enter title and content.
3. Click “Publish.”

Pages vs Posts:

• Pages are static (About, Contact)
• Not listed by date
• No categories or tags

Custom Page Template:

<?php
/* Template Name: Full Width Page */
get_header();
echo '<div>This is a full-width custom template</div>';
get_footer();

13. How do you set the homepage in WordPress?

Steps:

1. Go to Settings > Reading
2. Under “Your homepage displays”, select “A static page”

3. Choose:

   • Homepage: a page like “Home”
   • Posts page: a page like “Blog”
4. Save changes

Now visitors see the selected page instead of blog posts on the front page.

14. What is a permalink?

A permalink is the full, permanent URL to a specific post, page, or resource.

Examples:

• Default: /?p=123
• Clean: /my-post/

Set under: Settings > Permalinks

Recommended structure for blogs:

/%postname%/

Programmatic access:

$post_url = get_permalink($post->ID);

15. What are custom post types?

Custom Post Types (CPTs) let you define new content types beyond Posts and Pages.

Example: Portfolio items

Register CPT using named function:

function register_portfolio_post_type() {
    $args = array(
        'label' => 'Portfolio',
        'public' => true,
        'supports' => array('title', 'editor', 'thumbnail'),
        'has_archive' => true,
        'menu_icon' => 'dashicons-portfolio'
    );
    register_post_type('portfolio', $args);
}
add_action('init', 'register_portfolio_post_type');

What this does:

• Adds “Portfolio” to dashboard
• Enables new content structure
• Archives accessible at /portfolio/

Theme Development Basics

1. What files are required to create a basic WordPress theme?

To create a minimal but functional WordPress theme, you need at least two files:

1. style.css – contains the theme metadata and styling.
2. index.php – the main template file.

Optional (but recommended) files:

• functions.php – theme setup and feature support.
• screenshot.png – a preview image shown in the admin.
• header.php, footer.php, sidebar.php – template parts for structure.
• single.php, page.php, archive.php – to handle specific views.

style.css example:

/*
Theme Name: My First Theme
Author: Your Name
Version: 1.0
*/

2. What is the use of style.css in a WordPress theme?

style.css serves two roles:

1. Metadata declaration – Required header comment that tells WordPress the theme’s name, author, version, etc.
2. Main stylesheet – Contains CSS rules for styling the theme.

Example content:

/*
Theme Name: Custom Starter Theme
Author: Jane Doe
Version: 1.0
*/

body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
}

WordPress uses this file to recognize and list your theme in the dashboard.

3. What is the functions.php file used for?

functions.php is like the engine room of your theme. It is loaded automatically when the theme is active.

You use it to:

• Register theme features
• Enqueue styles/scripts
• Register menus, sidebars
• Add filters and actions

Example:

function mytheme_setup() {
    add_theme_support('title-tag');
    add_theme_support('post-thumbnails');
}
add_action('after_setup_theme', 'mytheme_setup');

4. How do you enqueue styles and scripts in WordPress?

Never use <link> or <script> tags directly. Use wp_enqueue_style() and wp_enqueue_script().

Correct way:

function mytheme_enqueue_assets() {
    wp_enqueue_style('mytheme-style', get_stylesheet_uri());
    wp_enqueue_script('mytheme-script', get_template_directory_uri() . '/assets/js/script.js', array(), '1.0', true);
}
add_action('wp_enqueue_scripts', 'mytheme_enqueue_assets');

Why enqueueing is important:

• Prevents conflicts
• Avoids duplicate loading
• Enables dependency management

5. What is the purpose of get_header() and get_footer()?

These functions include partial template files:

• get_header() loads header.php
• get_footer() loads footer.php

They’re used in main templates to follow DRY (Don’t Repeat Yourself) principles.

Example in index.php:

get_header();

echo '<main>';
if (have_posts()) {
    while (have_posts()) {
        the_post();
        the_content();
    }
}
echo '</main>';

get_footer();

6. What is the template hierarchy in WordPress?

The template hierarchy is the system WordPress uses to determine which theme file to load for different types of content.

Examples:

• A post: single-post.php → single.php → singular.php → index.php
• A page: page-{slug}.php → page-{id}.php → page.php → singular.php → index.php
• A category: category-{slug}.php → category.php → archive.php → index.php

WordPress starts with the most specific file and falls back to more general ones.

7. How do you create a custom page template?

You can define a custom template for individual pages by adding a comment at the top of a new PHP file in your theme.

Example: page-custom.php

<?php
/*
Template Name: Custom Landing Page
*/
get_header();
echo '<h1>This is a custom page template</h1>';
get_footer();

How to use:

1. Create a page in the admin
2. Select “Custom Landing Page” from the Template dropdown (in Page Attributes)

8. What is the_content() function?

the_content() outputs the main body content of a post or page from the database.

Usage:

if (have_posts()) {
    while (have_posts()) {
        the_post();
        the_content(); // outputs post/page content
    }
}

Note: It applies filters like shortcodes, paragraph formatting, and block rendering.

If you just want the raw content (without output), use get_the_content().

9. What is get_template_part() used for?

get_template_part() is used to include reusable template parts (e.g., post layout, content blocks).

Usage:

get_template_part('template-parts/content', 'single');

This looks for:

• template-parts/content-single.php
• If not found: template-parts/content.php

Benefits:

• Cleaner code
• Easy to reuse sections
• Follows separation of concerns

10. How do you create a custom sidebar?

You register a sidebar using register_sidebar() in functions.php.

Step 1: Register Sidebar

function mytheme_widgets_init() {
    register_sidebar(array(
        'name' => 'Main Sidebar',
        'id' => 'main_sidebar',
        'before_widget' => '<section class="widget">',
        'after_widget' => '</section>',
        'before_title' => '<h3>',
        'after_title' => '</h3>',
    ));
}
add_action('widgets_init', 'mytheme_widgets_init');

Step 2: Display in Template

if (is_active_sidebar('main_sidebar')) {
    dynamic_sidebar('main_sidebar');
}

11. How can you make a theme translation-ready?

To prepare your theme for translation:

Step 1: Add this in functions.php:

function mytheme_load_textdomain() {
    load_theme_textdomain('mytheme', get_template_directory() . '/languages');
}
add_action('after_setup_theme', 'mytheme_load_textdomain');

Step 2: Wrap all text with translation functions

_e('Read more', 'mytheme');

Step 3: Create a .pot file Use tools like Poedit or Loco Translate to generate translatable strings.

12. What is the wp_head() function?

wp_head() is a core WordPress function that outputs important code in the <head> section of your HTML.

You must call it in header.php just before </head>:

<head>
    <meta charset="<?php bloginfo('charset'); ?>">
    <?php wp_head(); ?>
</head>

What it does:

• Outputs enqueued styles/scripts
• Injects meta tags
• Adds plugin code (like SEO tags)

Without this, many plugins and features won’t work properly.

13. How do you add a featured image to a post?

Step 1: Enable in functions.php:

function mytheme_enable_thumbnails() {
    add_theme_support('post-thumbnails');
}
add_action('after_setup_theme', 'mytheme_enable_thumbnails');

Step 2: Set in Post Editor

• Edit a post
• Set a featured image using the right sidebar

Step 3: Display in template

if (has_post_thumbnail()) {
    the_post_thumbnail('medium'); // sizes: thumbnail, medium, large
}

14. How do you create a navigation menu?

Step 1: Register Menu in functions.php:

function mytheme_register_menus() {
    register_nav_menu('main_menu', 'Main Navigation Menu');
}
add_action('after_setup_theme', 'mytheme_register_menus');

Step 2: Assign it in Dashboard Appearance > Menus > Create and assign menu to “Main Navigation Menu”

Step 3: Display it in template

wp_nav_menu(array(
    'theme_location' => 'main_menu',
    'menu_class' => 'nav-menu'
));

15. How do you use is_page() and is_single()?

These are conditional functions used to check the current post/page type.

is_page() – returns true if viewing a specific page is_single() – returns true if viewing a blog post

Examples:

function my_custom_body_class($classes) {
    if (is_page('about')) {
        $classes[] = 'about-page';
    }
    if (is_single() && has_category('news')) {
        $classes[] = 'news-post';
    }
    return $classes;
}
add_filter('body_class', 'my_custom_body_class');

You can also pass page/post IDs or slugs:

is_page(42)
is_page('contact')
is_single('hello-world')

Plugin Development Basics

1. How do you create a basic WordPress plugin?

A WordPress plugin is simply a PHP file with a special comment header, placed inside the wp-content/plugins/ directory.

Steps:

1. Create a folder: wp-content/plugins/my-first-plugin
2. Inside it, create a PHP file: my-first-plugin.php

Example:

<?php
/**
 * Plugin Name: My First Plugin
 * Description: A simple plugin to display a message.
 * Version: 1.0
 * Author: Your Name
 */

function myfp_display_message() {
    echo '<p>Hello from My First Plugin!</p>';
}
add_action('wp_footer', 'myfp_display_message');

Then activate it via Dashboard > Plugins.

2. What is the plugin header comment?

The plugin header comment is a block of metadata required by WordPress to recognize a plugin.

It must appear at the top of the main plugin file.

Example:

/*
Plugin Name: Custom Widget Plugin
Plugin URI: https://example.com/custom-widget
Description: Adds a custom widget to the sidebar.
Version: 1.0
Author: John Doe
Author URI: https://example.com
License: GPL2
*/

This header allows WordPress to display plugin details in the admin area.

3. What is add_action() in WordPress?

add_action() connects your custom function to a specific action hook in WordPress.

It tells WordPress: “When this event happens, run this function.”

Example:

function myplugin_footer_text() {
    echo '<p>This site is powered by MyPlugin.</p>';
}
add_action('wp_footer', 'myplugin_footer_text');

In this case, when wp_footer is called in the theme, your function is executed.

4. What is add_filter()?

add_filter() is used to modify data before it is displayed or saved.

Example:

function myplugin_change_title($title) {
    return '🔥 ' . $title;
}
add_filter('the_title', 'myplugin_change_title');

This prepends a fire icon to every post title.

5. What are WordPress hooks?

Hooks are predefined points in WordPress execution where you can add or modify behavior.

There are two types:

• Actions: Do something (e.g., insert HTML, send email)
• Filters: Modify data (e.g., change post title)

Example hooks:

• wp_footer (action)
• the_content (filter)
• init (action)
• excerpt_length (filter)

Hooks allow plugins and themes to interact with WordPress core without modifying it.

6. What is the difference between actions and filters?

Action Example:

function myplugin_on_init() {
    // Run some custom logic on init
}
add_action('init', 'myplugin_on_init');

Filter Example:

function myplugin_modify_title($title) {
    return 'Modified: ' . $title;
}
add_filter('the_title', 'myplugin_modify_title');

7. How do you register a custom shortcode?

Use add_shortcode() with a named function that returns content.

Example:

function myplugin_hello_shortcode() {
    return '<p>Hello from shortcode!</p>';
}
add_shortcode('hello', 'myplugin_hello_shortcode');

Use it in content:

[hello]

This will output:

Hello from shortcode!

8. What is register_activation_hook() used for?

This function runs only once — when the plugin is activated.

Common uses:

• Create database tables
• Set default options

Example:

function myplugin_on_activation() {
    update_option('myplugin_enabled', true);
}
register_activation_hook(__FILE__, 'myplugin_on_activation');

You must call this in the main plugin file.

9. How can you include custom CSS/JS in a plugin?

Use wp_enqueue_style() and wp_enqueue_script() inside a function and hook it to wp_enqueue_scripts.

Example:

function myplugin_enqueue_assets() {
    wp_enqueue_style('myplugin-style', plugin_dir_url(__FILE__) . 'assets/style.css');
    wp_enqueue_script('myplugin-script', plugin_dir_url(__FILE__) . 'assets/script.js', array(), '1.0', true);
}
add_action('wp_enqueue_scripts', 'myplugin_enqueue_assets');

Make sure style.css and script.js exist in the plugin’s /assets/ folder.

10. What is a nonce in WordPress?

A nonce (Number used once) is a token used to verify that a request came from a legitimate source. It protects against CSRF (Cross-Site Request Forgery).

Create nonce for a form:

wp_nonce_field('myplugin_action', 'myplugin_nonce');

Verify it in PHP:

if (!isset($_POST['myplugin_nonce']) || !wp_verify_nonce($_POST['myplugin_nonce'], 'myplugin_action')) {
    wp_die('Invalid request');
}

Nonces expire after 24 hours by default.

11. How do you sanitize input in a plugin?

Always sanitize user input before using it.

Common functions:

• sanitize_text_field()
• sanitize_email()
• absint()
• esc_url()

Example:

function myplugin_save_name($name_input) {
    $name = sanitize_text_field($name_input);
    update_option('myplugin_name', $name);
}

Sanitizing prevents XSS, database injection, and other vulnerabilities.

12. How do you register a custom settings page?

You can create a settings page in the admin using add_menu_page().

Step 1: Register Page

function myplugin_admin_menu() {
    add_menu_page(
        'My Plugin Settings',
        'My Plugin',
        'manage_options',
        'myplugin-settings',
        'myplugin_render_settings_page'
    );
}
add_action('admin_menu', 'myplugin_admin_menu');

Step 2: Define Callback

function myplugin_render_settings_page() {
    echo '<div class="wrap"><h1>Plugin Settings</h1></div>';
}

You can expand this with form inputs and saving logic.

13. What is the use of the admin_menu hook?

The admin_menu hook is used to add items to the WordPress admin menu.

Examples:

• Create custom settings pages
• Add submenus under existing menus
• Control menu visibility with roles

Usage:

add_action('admin_menu', 'myplugin_add_menu');

function myplugin_add_menu() {
    add_menu_page('Title', 'My Menu', 'manage_options', 'myplugin', 'myplugin_render_page');
}

14. How do you handle form submissions in a plugin?

1. Display form with nonce:

function myplugin_form_output() {
    echo '<form method="post">';
    wp_nonce_field('myplugin_submit', 'myplugin_nonce');
    echo '<input type="text" name="my_name">';
    echo '<input type="submit" name="submit_button">';
    echo '</form>';
}

2. Handle form data:

function myplugin_process_form() {
    if (isset($_POST['submit_button']) && check_admin_referer('myplugin_submit', 'myplugin_nonce')) {
        $name = sanitize_text_field($_POST['my_name']);
        update_option('myplugin_saved_name', $name);
    }
}
add_action('admin_init', 'myplugin_process_form');

Always sanitize input and verify nonces.

15. What is wp_enqueue_script()?

This function adds JavaScript files to WordPress pages in a proper, safe, and dependency-aware way.

Syntax:

wp_enqueue_script(
    $handle,            // unique name
    $src,               // path to script
    $deps = array(),    // dependencies (e.g. ['jquery'])
    $ver = false,       // version number
    $in_footer = false  // load in footer?
);

Example:

function myplugin_load_scripts() {
    wp_enqueue_script('myplugin-js', plugin_dir_url(__FILE__) . 'assets/main.js', array('jquery'), '1.0', true);
}
add_action('wp_enqueue_scripts', 'myplugin_load_scripts');

This ensures:

• No duplicate loading
• Script runs in the right place
• Dependency like jQuery is loaded first

Database and Core Functions

1. What is the default table prefix in WordPress?

The default table prefix is:

wp_

So WordPress creates tables like:

• wp_posts
• wp_users
• wp_options

You can customize the prefix during installation (for example, abc_). This helps avoid conflicts and slightly improves security by obscuring default table names.

2. How do you access the database in WordPress?

WordPress provides an object called $wpdb to access the database.

You don’t need to write raw MySQL code or connect manually. $wpdb handles:

• Safe queries
• Prepared statements
• Table prefixes

Basic usage:

function get_total_post_count() {
    global $wpdb;
    $count = $wpdb->get_var("SELECT COUNT(*) FROM {$wpdb->posts} WHERE post_type = 'post'");
    return $count;
}

3. What is $wpdb?

$wpdb is a WordPress global object that provides an interface to interact with the WordPress database.

It is an instance of the wpdb class and gives access to methods like:

• get_results()
• get_var()
• insert()
• update()
• delete()
• prepare()

It also holds all table names with the correct prefix, like $wpdb->posts, $wpdb->users, $wpdb->options.

Example:

function get_post_titles() {
    global $wpdb;
    return $wpdb->get_col("SELECT post_title FROM {$wpdb->posts} WHERE post_status = 'publish'");
}

4. How do you write a custom SQL query in WordPress?

Use $wpdb to write safe and efficient SQL queries. Use prepare() to avoid SQL injection.

Example:

function get_author_posts($author_id) {
    global $wpdb;
    $sql = $wpdb->prepare("SELECT post_title FROM {$wpdb->posts} WHERE post_author = %d AND post_status = 'publish'", $author_id);
    return $wpdb->get_col($sql);
}

• %d for integers
• %s for strings

Always use prepare() when inserting variables into SQL queries.

5. What is the purpose of get_option() and update_option()?

These functions allow you to retrieve and store settings in the wp_options table.

• get_option( $name ): retrieves a value
• update_option( $name, $value ): saves or updates a value

Example:

function save_plugin_setting() {
    update_option('myplugin_enabled', true);
}

function get_plugin_setting() {
    return get_option('myplugin_enabled');
}

Use these for plugin settings, theme options, and general configurations.

6. How do you add a custom meta field to posts?

Use add_post_meta() to add new meta or update_post_meta() to update it.

Example:

function set_reading_time($post_id, $minutes) {
    update_post_meta($post_id, 'reading_time', absint($minutes));
}

To retrieve it:

function get_reading_time($post_id) {
    return get_post_meta($post_id, 'reading_time', true);
}

Meta fields are stored in wp_postmeta.

7. What are post meta and user meta?

Both are types of custom fields attached to posts or users:

• Post Meta: Data related to a post (e.g., reading_time, featured_color)

  • Stored in wp_postmeta
  • Use: add_post_meta(), get_post_meta()

• User Meta: Data related to users (e.g., phone_number, profile_visibility)

  • Stored in wp_usermeta
  • Use: add_user_meta(), get_user_meta()

Example:

function set_user_bio($user_id, $bio) {
    update_user_meta($user_id, 'custom_bio', sanitize_text_field($bio));
}

8. How do you create a custom table in WordPress?

Use dbDelta() inside register_activation_hook() to safely create tables.

Example:

function myplugin_create_table() {
    global $wpdb;
    $table = $wpdb->prefix . 'my_custom_table';
    $charset = $wpdb->get_charset_collate();

    $sql = "CREATE TABLE $table (
        id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
        name VARCHAR(255) NOT NULL,
        created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
        PRIMARY KEY (id)
    ) $charset;";

    require_once ABSPATH . 'wp-admin/includes/upgrade.php';
    dbDelta($sql);
}

register_activation_hook(__FILE__, 'myplugin_create_table');

Always include upgrade.php and use dbDelta() for safe, update-aware table creation.

9. What is a transient in WordPress?

A transient is a way to store temporary data in the database with an expiration time.

Useful for caching expensive queries or API responses.

Set transient:

function store_api_response($data) {
    set_transient('api_cache_key', $data, HOUR_IN_SECONDS);
}

Get transient:

function get_cached_api_data() {
    return get_transient('api_cache_key');
}

Delete transient:

delete_transient('api_cache_key');

Stored in the wp_options table with an _transient_ prefix.

10. How do you delete a WordPress option?

Use delete_option() to permanently remove an option from the wp_options table.

Example:

function remove_plugin_option() {
    delete_option('myplugin_enabled');
}

If the option doesn’t exist, WordPress simply skips it without error.

11. What is the difference between get_post_meta() and get_option()?

Use get_post_meta() when the data is tied to a specific post or page. Use get_option() for global plugin or theme settings.

12. How can you import data into WordPress programmatically?

Use functions like wp_insert_post(), wp_insert_user(), update_post_meta().

Example: Add posts from an array

function import_blog_posts($posts) {
    foreach ($posts as $post_data) {
        $post_id = wp_insert_post(array(
            'post_title'   => $post_data['title'],
            'post_content' => $post_data['content'],
            'post_status'  => 'publish',
            'post_type'    => 'post'
        ));
        update_post_meta($post_id, 'source', 'imported');
    }
}

Always sanitize and validate incoming data before saving.

13. What is wp_insert_post()?

This function adds or updates a post in the database.

Example:

function create_new_post() {
    $post_id = wp_insert_post(array(
        'post_title'   => 'My New Post',
        'post_content' => 'This is the content.',
        'post_status'  => 'publish',
        'post_type'    => 'post'
    ));
    return $post_id;
}

You can use it for posts, pages, or custom post types. If ID is included in the array, it will update that post instead of creating a new one.

14. How do you check if a post exists in the database?

Check using get_page_by_title(), get_post(), or a custom query.

Example: Check by title

function does_post_exist($title) {
    $existing_post = get_page_by_title($title, OBJECT, 'post');
    return $existing_post ? $existing_post->ID : false;
}

Or check by ID:

function is_post_valid($post_id) {
    return get_post($post_id) !== null;
}

15. What is the use of prepare() method with $wpdb?

$wpdb->prepare() is used to safely insert variables into SQL queries and prevent SQL injection.

Syntax:

$wpdb->prepare( $query, $value1, $value2 );

Example:

function get_posts_by_author($author_id) {
    global $wpdb;
    $sql = $wpdb->prepare("SELECT * FROM {$wpdb->posts} WHERE post_author = %d", $author_id);
    return $wpdb->get_results($sql);
}

Placeholders:

• %d for integers
• %s for strings
• %f for floats

Always use prepare() when inserting user input into SQL.

WooCommerce Basics

1. What is WooCommerce?

WooCommerce is a free WordPress plugin that transforms your WordPress site into a fully functional ecommerce store.

What it does:

• Lets you sell physical and digital products
• Manages inventory, taxes, shipping
• Supports payments (PayPal, Stripe, UPI, etc.)
• Offers thousands of add-ons (subscriptions, bookings, memberships)

Built by Automattic, it’s the most popular ecommerce solution for WordPress.

2. How do you install WooCommerce on a WordPress site?

Steps:

1. Go to Plugins > Add New
2. Search for WooCommerce
3. Click Install Now → then Activate

After activation:

• WooCommerce creates pages: Shop, Cart, Checkout, My Account
• A setup wizard will guide you through currency, shipping, and payment settings

3. What is a WooCommerce product?

A product in WooCommerce is a post of the product custom post type. Each product contains:

• Title
• Description
• Price
• Inventory status
• Categories and tags
• Product type (simple, variable, etc.)

Products are stored in the wp_posts table and extended using postmeta.

4. What are the different product types in WooCommerce?

WooCommerce supports the following product types:

1. Simple Product – A physical item with no variations
2. Variable Product – Has variations like size or color
3. Grouped Product – Collection of simple products sold together
4. External/Affiliate Product – Links to another website
5. Downloadable Product – Digital files
6. Virtual Product – Services or non-physical items

Each type is handled differently in the backend and checkout logic.

5. How do you create a simple product in code?

You can use wp_insert_post() and update_post_meta() to create a WooCommerce product.

Example:

function create_simple_woo_product() {
    $post_id = wp_insert_post(array(
        'post_title'   => 'Test Product',
        'post_content' => 'This is a test product.',
        'post_status'  => 'publish',
        'post_type'    => 'product'
    ));

    update_post_meta($post_id, '_regular_price', '29.99');
    update_post_meta($post_id, '_price', '29.99');
    update_post_meta($post_id, '_stock_status', 'instock');
}

6. How can you customize the “Add to Cart” button text?

Use the woocommerce_product_single_add_to_cart_text and woocommerce_product_add_to_cart_text filters.

Example:

function custom_add_to_cart_button_text() {
    return 'Buy Now';
}
add_filter('woocommerce_product_single_add_to_cart_text', 'custom_add_to_cart_button_text');
add_filter('woocommerce_product_add_to_cart_text', 'custom_add_to_cart_button_text');

Applies to both archive and single product pages.

7. What are WooCommerce hooks?

WooCommerce hooks are similar to WordPress hooks—they let you run custom code or modify output at specific points in WooCommerce templates or processes.

Two types:

• Actions – Add custom HTML or logic (add_action)
• Filters – Modify values (add_filter)

Examples:

• woocommerce_before_main_content
• woocommerce_add_cart_item_data
• woocommerce_cart_calculate_fees

8. What is the function of woocommerce_before_main_content?

This is an action hook fired at the beginning of the content area on shop-related pages (shop, single product, category).

Used to:

• Insert banners, breadcrumbs, custom notices
• Wrap content in layout markup

Example:

function add_custom_banner_before_products() {
    echo '<div class="banner">Summer Sale is Live!</div>';
}
add_action('woocommerce_before_main_content', 'add_custom_banner_before_products');

9. How do you enqueue styles in a WooCommerce-compatible theme?

WooCommerce-compatible themes use add_theme_support( 'woocommerce' ) and enqueue their own styles using wp_enqueue_style.

Step 1: Declare compatibility in functions.php:

function mytheme_add_woocommerce_support() {
    add_theme_support('woocommerce');
}
add_action('after_setup_theme', 'mytheme_add_woocommerce_support');

Step 2: Enqueue styles:

function mytheme_enqueue_woo_styles() {
    if (class_exists('WooCommerce')) {
        wp_enqueue_style('mytheme-woocommerce', get_template_directory_uri() . '/css/woocommerce.css');
    }
}
add_action('wp_enqueue_scripts', 'mytheme_enqueue_woo_styles');

10. How do you override WooCommerce templates?

Steps:

1. Copy the WooCommerce template from: wp-content/plugins/woocommerce/templates/

2. Paste it into your theme like: yourtheme/woocommerce/single-product/title.php

3. Modify as needed.

WooCommerce will load the template from the theme directory instead of its default location.

Always maintain directory structure.

11. What file handles the single product layout?

The main file is:

woocommerce/single-product.php

It includes partials like:

• title.php
• price.php
• add-to-cart/simple.php
• tabs/tabs.php

You can override each part by copying the corresponding file into your theme’s woocommerce folder.

12. How do you add a custom tab to the product page?

Use the woocommerce_product_tabs filter.

Example:

function add_custom_product_tab($tabs) {
    $tabs['custom_tab'] = array(
        'title'    => 'More Info',
        'priority' => 50,
        'callback' => 'render_custom_product_tab_content'
    );
    return $tabs;
}
add_filter('woocommerce_product_tabs', 'add_custom_product_tab');

function render_custom_product_tab_content() {
    echo '<p>This is extra info added via a custom tab.</p>';
}

13. How can you add a custom fee during checkout?

Hook into woocommerce_cart_calculate_fees.

Example:

function add_handling_fee_to_checkout($cart) {
    if (is_admin() && !defined('DOING_AJAX')) return;
    $cart->add_fee('Handling Fee', 5.00);
}
add_action('woocommerce_cart_calculate_fees', 'add_handling_fee_to_checkout');

This adds a fixed fee visible on the checkout page.

14. What is the function to get the cart total?

Use:

WC()->cart->get_total();        // Formatted string with currency
WC()->cart->get_cart_total();  // Similar to get_total()
WC()->cart->get_cart_contents_total(); // Numeric value without tax/shipping

Example:

function show_cart_total_notice() {
    $total = WC()->cart->get_cart_contents_total();
    wc_add_notice("Cart subtotal: ₹" . $total, 'notice');
}
add_action('woocommerce_before_checkout_form', 'show_cart_total_notice');

15. How do you programmatically create an order?

Use the WC_Order class.

Example:

function create_programmatic_order() {
    $address = array(
        'first_name' => 'John',
        'last_name'  => 'Doe',
        'email'      => 'john@example.com',
        'address_1'  => '123 Street',
        'city'       => 'Calicut',
        'postcode'   => '673001',
        'country'    => 'IN'
    );

    $order = wc_create_order();
    $order->add_product(wc_get_product(123), 1); // Product ID, quantity
    $order->set_address($address, 'billing');
    $order->calculate_totals();
    $order->update_status('processing');

    return $order->get_id();
}

This creates an order, adds a product, and sets billing details.

JavaScript & jQuery in WordPress

1. How do you enqueue a JavaScript file in WordPress?

To add a JavaScript file properly, use wp_enqueue_script() inside a function, then hook it to wp_enqueue_scripts.

Example:

function enqueue_custom_script() {
    wp_enqueue_script(
        'custom-js', 
        get_template_directory_uri() . '/js/custom.js', 
        array('jquery'), 
        '1.0.0', 
        true // Load in footer
    );
}
add_action('wp_enqueue_scripts', 'enqueue_custom_script');

• array('jquery') sets jQuery as a dependency.
• true loads the script in the footer for better performance.

2. What is wp_localize_script() used for?

wp_localize_script() is used to pass PHP data to JavaScript — especially useful for AJAX URLs and nonces.

Example:

function localize_ajax_data() {
    wp_enqueue_script('custom-js', get_template_directory_uri() . '/js/custom.js', array('jquery'), null, true);

    $ajax_data = array(
        'ajax_url' => admin_url('admin-ajax.php'),
        'nonce'    => wp_create_nonce('custom_nonce')
    );

    wp_localize_script('custom-js', 'my_ajax_obj', $ajax_data);
}
add_action('wp_enqueue_scripts', 'localize_ajax_data');

In your custom.js:

console.log(my_ajax_obj.ajax_url);

3. How do you make a simple AJAX request in WordPress?

Step 1: Localize script with admin-ajax.php and nonce (as shown above).

Step 2: JavaScript/jQuery AJAX

jQuery(document).ready(function($) {
    $('#getData').on('click', function() {
        $.ajax({
            url: my_ajax_obj.ajax_url,
            method: 'POST',
            data: {
                action: 'fetch_data',
                security: my_ajax_obj.nonce
            },
            success: function(response) {
                $('#result').html(response);
            }
        });
    });
});

Step 3: Handle it in PHP

function handle_ajax_request() {
    check_ajax_referer('custom_nonce', 'security');

    echo 'This is data from PHP!';
    wp_die();
}
add_action('wp_ajax_fetch_data', 'handle_ajax_request');
add_action('wp_ajax_nopriv_fetch_data', 'handle_ajax_request');

4. How do you pass a nonce to JavaScript?

Use wp_create_nonce() to generate the nonce, and wp_localize_script() to pass it.

PHP:

function pass_nonce_to_js() {
    wp_enqueue_script('my-js', get_template_directory_uri() . '/js/my.js', array('jquery'), null, true);

    $nonce_data = array(
        'nonce' => wp_create_nonce('secure_action')
    );

    wp_localize_script('my-js', 'my_nonce_obj', $nonce_data);
}
add_action('wp_enqueue_scripts', 'pass_nonce_to_js');

JavaScript:

var nonce = my_nonce_obj.nonce;

Use it in AJAX for security validation.

5. What is the admin-ajax.php file?

admin-ajax.php is a core WordPress file that handles AJAX requests on both front end and admin.

AJAX URL:

admin_url('admin-ajax.php')

Common use:

• Define an action value
• Use add_action('wp_ajax_...') and optionally wp_ajax_nopriv_...

This allows plugin or theme developers to process AJAX safely and within WordPress.

6. How do you detect if jQuery is loaded in your theme?

You can:

1. Check the source code (view-source: or dev tools) for a jQuery <script> tag.
2. Run this in the browser console:

typeof jQuery !== 'undefined' // should return true

Proper way to include jQuery in your theme:

function ensure_jquery_loaded() {
    wp_enqueue_script('jquery');
}
add_action('wp_enqueue_scripts', 'ensure_jquery_loaded');

This loads WordPress’s built-in version of jQuery.

7. What is the difference between $(document).ready() and window.onload?

Example using jQuery:

jQuery(document).ready(function($) {
    // Safe to manipulate DOM here
});

8. How do you add click event listeners with jQuery?

Use the .on() method for attaching event listeners.

Example:

jQuery(document).ready(function($) {
    $('#myButton').on('click', function() {
        alert('Button clicked!');
    });
});

Using .on() is preferred over .click() because it’s compatible with dynamically added elements.

9. How do you safely load jQuery in a WordPress theme?

Use wp_enqueue_script() and declare 'jquery' as a dependency.

Example:

function load_jquery_in_theme() {
    wp_enqueue_script('theme-js', get_template_directory_uri() . '/js/theme.js', array('jquery'), null, true);
}
add_action('wp_enqueue_scripts', 'load_jquery_in_theme');

This ensures WordPress loads jQuery only once and in the correct order.

10. How can you submit a form via AJAX?

Step 1: Add the form in HTML

<form id="contactForm">
    <input type="text" name="name" required />
    <input type="submit" value="Send" />
</form>
<div id="response"></div>

Step 2: JavaScript

jQuery(document).ready(function($) {
    $('#contactForm').on('submit', function(e) {
        e.preventDefault();

        $.ajax({
            url: my_ajax_obj.ajax_url,
            method: 'POST',
            data: {
                action: 'submit_form',
                name: $('input[name="name"]').val(),
                security: my_ajax_obj.nonce
            },
            success: function(res) {
                $('#response').html(res);
            }
        });
    });
});

Step 3: PHP handler

function handle_form_submission() {
    check_ajax_referer('custom_nonce', 'security');

    $name = sanitize_text_field($_POST['name']);
    echo 'Thanks, ' . esc_html($name) . '!';

    wp_die();
}
add_action('wp_ajax_submit_form', 'handle_form_submission');
add_action('wp_ajax_nopriv_submit_form', 'handle_form_submission');

REST API Basics

1. What is the WordPress REST API?

The WordPress REST API is a feature that allows external applications to communicate with your WordPress site using HTTP.

• It supports GET, POST, PUT, DELETE, and more.
• Data is sent and received as JSON.
• You can access posts, users, comments, and more, or register custom endpoints.

Example:

GET https://example.com/wp-json/wp/v2/posts

REST API allows WordPress to be used as a headless CMS or to integrate with React, Vue, mobile apps, and third-party tools.

2. What is an endpoint in the REST API?

An endpoint is a specific URL path that the API listens to and responds from.

Structure:

/wp-json/{namespace}/{route}

Example endpoints:

• /wp-json/wp/v2/posts → retrieves posts
• /wp-json/wp/v2/pages → retrieves pages

You can create custom endpoints like:

/wp-json/myplugin/v1/custom-data

Each endpoint maps to a specific callback function that processes the request and returns a response.

3. How do you fetch posts using the REST API?

You can fetch posts using a GET request to the following URL:

GET https://example.com/wp-json/wp/v2/posts

To fetch specific fields or filters:

GET https://example.com/wp-json/wp/v2/posts?per_page=5&orderby=date

You can use tools like:

• JavaScript fetch()
• jQuery $.ajax()
• REST API clients like Postman

Example in JS:

fetch('/wp-json/wp/v2/posts')
  .then(response => response.json())
  .then(data => console.log(data));

4. How do you register a custom REST API route?

Use register_rest_route() inside the rest_api_init action hook.

Example:

function myplugin_register_custom_route() {
    register_rest_route('myplugin/v1', '/greeting', array(
        'methods'  => 'GET',
        'callback' => 'myplugin_handle_greeting_request'
    ));
}
add_action('rest_api_init', 'myplugin_register_custom_route');

function myplugin_handle_greeting_request() {
    return array('message' => 'Hello from the custom REST API route!');
}

This creates a new route:

GET /wp-json/myplugin/v1/greeting

5. What is register_rest_route()?

register_rest_route() is a WordPress function used to define custom REST API endpoints.

Syntax:

register_rest_route($namespace, $route, $args);

• $namespace: Grouping (e.g., myplugin/v1)
• $route: Path (e.g., /data)
• $args: Array of settings (methods, callback, permissions)

Example:

register_rest_route('myplugin/v1', '/data', array(
    'methods' => 'GET',
    'callback' => 'myplugin_get_data'
));

6. How do you send data using a POST request in the REST API?

You send a POST request to a custom or built-in endpoint with JSON or form data in the body.

Example (JavaScript with fetch):

fetch('/wp-json/myplugin/v1/save', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-WP-Nonce': my_ajax_obj.nonce
  },
  body: JSON.stringify({ name: 'John Doe' })
})
.then(response => response.json())
.then(data => console.log(data));

PHP handler:

function myplugin_save_data(WP_REST_Request $request) {
    $name = sanitize_text_field($request->get_param('name'));
    return array('message' => 'Saved: ' . $name);
}

Always sanitize and validate input in POST endpoints.

7. What is wp_send_json_success()?

This function sends a JSON response with a success status and optional data.

Example:

function myplugin_return_data() {
    $data = array('message' => 'Everything worked!');
    wp_send_json_success($data);
}

Output:

{
  "success": true,
  "data": {
    "message": "Everything worked!"
  }
}

There’s also wp_send_json_error() for errors.

Use these functions when building AJAX or REST responses manually.

8. How do you protect REST API routes with nonces?

Use check_ajax_referer() or wp_verify_nonce() in your endpoint to ensure the request is secure.

Step 1: Pass nonce to JS using wp_localize_script:

function enqueue_nonce_script() {
    wp_enqueue_script('my-js', get_template_directory_uri() . '/js/app.js', array('jquery'), null, true);

    wp_localize_script('my-js', 'my_ajax_obj', array(
        'nonce' => wp_create_nonce('wp_rest')
    ));
}
add_action('wp_enqueue_scripts', 'enqueue_nonce_script');

Step 2: Add permission_callback check:

function myplugin_check_permission() {
    return current_user_can('edit_posts') && check_ajax_referer('wp_rest', 'X-WP-Nonce', false);
}

function myplugin_secure_route() {
    register_rest_route('myplugin/v1', '/secure-data', array(
        'methods'             => 'POST',
        'callback'            => 'myplugin_handle_secure',
        'permission_callback' => 'myplugin_check_permission'
    ));
}
add_action('rest_api_init', 'myplugin_secure_route');

function myplugin_handle_secure(WP_REST_Request $request) {
    return array('status' => 'OK');
}

9. What is the difference between GET and POST methods?

Use GET when no side effects are expected (read-only). Use POST for actions that modify server-side data.

10. How do you view the REST API base URL for a site?

The REST API base URL for any WordPress site is:

https://yourdomain.com/wp-json/

You can test it by visiting:

https://yourdomain.com/wp-json/wp/v2/posts

This returns a JSON list of blog posts.

You can also explore all registered routes using:

https://yourdomain.com/wp-json

This is helpful when testing with Postman or inspecting available routes for custom development.