Top 200 Question and answers for Senior Fullstack WordPress Developer Interview in 2023

Top 200 Question and answers for Senior Fullstack WordPress Developer Interview in 2023

Question List for Senior WordPress Developer

GENERAL Questions - ⇓

  1. What is WordPress action hooks and Filter hook ? Tell us major different between them.
  2. Which WordPress coding standard’s do you follow ?
  3. How to implement proper security to our website ?
  4. How to improve site performance or speed ?

WordPress Database Questions ⇓

  1. How many table in the WordPress database ?
  2. What is Taxonomy in WordPress? Which tables uses to maintain taxonomy and this relationships?

WordPress Post - Post Type Questions ⇓

  1. How many post type WordPress has?
  2. Tell about custom WordPress post type ?
  3. What is the process of WordPress loop or the loop?

AJAX Questions ⇓

  1. What is Admin AJAX and it’s benefits ?
  2. How could you prevent XSS attack while ajax ?
  3. How to handle authenticated and un-authenticated ajax request ?

WordPress REST API Questions ⇓

  1. Why WordPress REST API instead of AJAX?
  2. How to add WordPress Rest API authentication?
  3. What the schema can do in WordPress Rest API?
  4. What we have to do make every request validation in WordPress REST API?
  5. Do you know about apiFetch library of WordPress?

WordPress Caching Questions

  1. What is Object Cache in WordPress and How to make an Object Cache?
  2. What is Transient Cache in WordPress?
  3. Which is the best times to use Object Cache or Transient Cache?
  4. Do you heard the topic Cache Invalidation? What does it mean?
  5. Is there any method to delete group of cache in WordPress, If not how will you handle to delete group of cache?

WordPress Data-flow - Loading architectures Questions ⇓

  1. How can I make system so that this plugin must have to install other plugin before run.
  2. What is Must-use plugin or MU plugins ?
  3. What is Multisite of WordPress, how WordPress handles multi-sites of WordPress ?
  4. Have you use WP CLI, What’s the benefits?
  5. What is processed first in WordPress - plugins or themes?

React JS Questions

  1. How react works under the hood?
  2. Tell us your React JS experiences?
  3. Where you’d load first time component loaded data in React the latest hooks way?
  4. What is custom hook in React?
  5. How to create a custom hook in React?

Redux Questions

  1. What is Redux?
  2. Do you know about WordPress data and is this same as Redux?
  3. What is generator function in redux saga?
  4. What is yield in Redux-saga?

Gutenberg Block Development Questions

  1. What is WordPress Gutenberg block and it’s uses?
  2. Can you develop a Custom Gutenberg block?
  3. Which Component you must have to use to make settings section for a block?
  4. How can you change text bold, alignment for a block or which component you should use ?
  5. Write a Simple block which can change a Title of the text, which will have to be from settings also ?

PHP & Design Pattern Questions

  1. What is Unit Testing and is that important in WordPress Coding practices?
  2. What is Composer, Will you use composer in your project?
  3. Why namespacing is important for maintaining code-base in PHP?
  4. What is PHP OOP?
  5. What is PHP Trait?
  6. What is Abstract class and difference with normal class in PHP?
  7. Do you follow Design patterns ? Tell us some of design pattern we should consider?
  8. Tell about SOLID principle
  9. Tell about Singleton design pattern

Github Questions ⇓

  1. What is Git Rebase ?
  2. What is Git Squash Merge?

Software Engineering Processes Questions ⇓

  1. Which coding methodology you use in your organization?
  2. Which softwares do you use to manage tasks?

Senior WordPress Developer Question Answers

GENERAL Question Answers

Q: What is WordPress hooks and Filter ? Tell us major different between them.

Answer:
Hooks - Hooks are the heart of WordPress ecosystem, which gives WordPress the power to modify any data or do anything on run-time.
Action hooks - It run and do something at specific time. It doesn’t return any value.
Filter hooks - It run and do something at specific time, modify the data and return the modified data.

Q: Which WordPress coding standard’s do you follow?

Answer: WordPress has some language specific coding standards. This can help to avoid common coding errors, improve the readability of the code. This ensures full code-base maintained in a same manner today or future. They are -

  1. HTML Coding Standards - Read at Developer.WordPress
  2. CSS Coding Standards - Read at Developer.WordPress
  3. JavaScript Coding Standards - Read at Developer.WordPress
  4. PHP Coding Standards - Read at Developer.WordPress

Q: How to implement proper security to our website?

Answer: We can follow this step by step to implement proper security to any WordPress site -

  1. Handle any request validation -
    1. Nonce validation to prevent XSS attack.
    2. Input validations as expected from frontend
  2. Check Authentication - Check proper authentication if user is authenticated or not.
  3. Check Authorization - Check authorization if user has access to that role or permission to do that thing.
  4. 2FA Login plugin implement for customer

Q: How to improve site performance or speed?

Answer: We can follow this step by step to improve Speed to any WordPress site -

  1. Install Caching Plugin - Instal Redis, W3 Total Cache etc on server.
  2. Object Cache - Implement in memory caching using WordPress object cache -wp_cache_add() wp_cache_get(), wp_cache_set(), wp_cache_flush(), wp_cache_delete()
  3. Page specific asset loading (JS/CSS) - Before loading any page, JS and CSS will only be enqueed page specific.
  4. Enable Server GZip -

WordPress Database Question Answers

Q: How many table in the WordPress database?

Answer: WordPress has 12 default tables -

  1. wp_commentmeta : This table contains meta information about comments posted on a WordPress website. The table has four fields meta_id, comment_id, meta_key, and meta_value. Each meta_id is related to a comment_id. One example of comment meta information stored is the status of comment (approved, pending, trash, etc).
  2. wp_comments : As the name suggests this table contains your WordPress comments. It contains the comment author name, URL, email, comment, etc.
  3. wp_links : To manage blogrolls created by earlier versions of WordPress or the Link Manager plugin.
  4. wp_options : This table contains most of your WordPress site-wide settings such as site URL, admin email, default category, posts per page, time format, and much much more. The options table is also used by numerous WordPress plugins to store plugin settings.
  5. wp_postmeta : This table contains meta-information about your WordPress posts, pages, and custom post types. Examples of post meta information would be which template to use to display a page, custom fields, etc. Some plugins would also use this table to store plugin data such as WordPress SEO information.
  6. wp_posts : The name says posts, but actually this table contains all post types or should we say content types. This table contains all your posts, pages, revisions, and custom post types.
  7. wp_termmeta : This table allows developers to store custom metadata for terms under their custom taxonomies. For example, WooCommerce uses it to store metadata for product attributes and categories.
  8. wp_terms : WordPress has a powerful taxonomy system that allows you to organize your content. Individual taxonomy items are called terms, and they are stored in this table. For example, your WordPress categories and tags are taxonomies, and each category/tag inside them is a term.
  9. wp_term_relationships : This table manages relationship of WordPress post types with terms in wp_terms table. For example, this is the table that helps WordPress determine post X is in Y category.
  10. wp_term_taxonomy : This table defines taxonomies for terms defined in wp_terms table. For example, if you have a term “WordPress Tutorials”, then this table contains the data that says it is associated with a taxonomy called category. In short, this table has the data that helps WordPress differentiate between which term is a category, which is a tag, etc.
  11. wp_usermeta : Contains meta information about registered users on your website.
  12. wp_users : Contains user information like username, password, user email, etc.

Q: What is Taxonomy in WordPress? Which tables uses to maintain taxonomy and this relationships?

Answer: In WordPress, Taxonomy is a way to group posts and custom post types together based on shared characteristics. It is essentially a way to organize and classify content on a website.

WordPress uses two main types of taxonomies:

  • Categories - used for broad grouping of posts
  • Tags - used for more specific grouping of posts

WordPress also allows for the creation of custom taxonomies for more specialized grouping of content. Taxonomy data in WordPress is stored in several tables in the database:

  • wp_terms - stores the term names and slugs
  • wp_term_taxonomy - stores the term taxonomy ID, term ID, taxonomy name, and other details
  • wp_term_relationships - associates terms with their corresponding posts or custom post types

The wp_terms table stores the name and slug for each term, and the wp_term_taxonomy table stores additional metadata about each term, including its taxonomy and description. The wp_term_relationships table stores the relationships between the terms and their associated posts or custom post types.

WordPress Post - Post Type Answers

Q: How many post type WordPress has?

Answer: WordPress has 5 post types -

    • Post
    • Page
    • Attachment
    • Revision
    • Menu

Q: Tell about custom WordPress post type?

Answer: We can create custom post type in WordPress using register_post_type() method.

function wporg_custom_post_type() {
	register_post_type('wporg_product',
		array(
			'labels'      => array(
				'name'          => __('Products', 'textdomain'),
				'singular_name' => __('Product', 'textdomain'),
			),
				'public'      => true,
				'has_archive' => true,
		)
	);
}
add_action('init', 'wporg_custom_post_type');

Q: What is the process of WordPress loop or the loop?

Answer: The WordPress Loop is the code that WordPress uses to display content on your website. Whenever entering into this loop variable, wordpress register data on some of the global variables.

Example -

if ( have_posts() ) :
        while ( have_posts() ) :
            the_post(); 
            //
            // Post Content here
            //
	endwhile; // end while
endif; // end if

AJAX Question Answers

Q: What is Admin AJAX and it’s benefits?

Answer: To send asynchronous request to server, we can use admin_ajax.
Advantages

  1. It directly outputs the HTML content or normal content, which can be used anywhere.
  1. It has separate functions for logged-in and logged-out users. While you can do this with a conditional in the REST-API, some may find this useful Working with the response is easier, since all you need is to put it in a div or wherever you need

Disadvantages
Since the output is plain HTML ( By default ) it shouldn’t ( or maybe even can’t ) be used in APIs and application development.

Q: How could you prevent XSS attack while ajax?

Answer: Before processing any GET or POST or any type of request, we should use nonce verification which will prevent from XSS.

Q: How to handle authenticated and un-authenticated ajax request?

Answer: We can use

  1. wp_ajax_{action_name} action hook to authenticated request and
  2. wp_ajax_nopriv_{action_name} action hook to un-authenticated request
add_action('wp_ajax_get_post_info', 'get_post_info');
add_action('wp_ajax_nopriv_get_post_info', 'get_post_info');

function get_post_info() {
   // Make your array as json
	wp_send_json([]);
 
    // Don't forget to stop execution afterward.
    wp_die();
}

Get more about WordPress ajax - https://developer.wordpress.org/reference/hooks/wp_ajax_action

WordPress Rest API Question Answers

Q: Why WordPress REST API instead of AJAX?

Answer: It offers a range of features and tools for building and managing websites, including the ability to make use of AJAX for interacting with the server and updating the page without the need for a full page refresh. However, in recent years, the WordPress REST API has emerged as a powerful alternative to AJAX for building more flexible and scalable applications.

  1. One key advantage of the WordPress REST API over AJAX is that it allows developers to build applications that can interact with the WordPress backend over HTTP, rather than just within the context of a single page. This means that developers can create standalone applications that can retrieve and update data from WordPress, as well as integrate WordPress functionality into other applications or websites.
  2. Another advantage of the WordPress REST API is that it is based on the principles of REST (Representational State Transfer), which is a well-established architectural style for building web services. This makes it easier for developers to understand and work with, as well as enabling better interoperability with other systems and APIs.
  3. Additionally, the WordPress REST API is designed to be more flexible and extensible than AJAX. It allows developers to create custom endpoints and routes for retrieving and manipulating data, as well as to make use of advanced features such as OAuth authentication and JSON Web Tokens for secure, token-based authentication.
    Overall, the WordPress REST API provides a more robust and flexible platform for building applications and integrations with WordPress, and is well worth considering as an alternative to AJAX for developers looking to take their WordPress projects to the next level.

Q: How to add WordPress Rest API authentication?

Answer: If you are working with the WordPress Rest API, you may find that you need to add authentication to the permission_callback method in order to secure your API endpoint. This can be done in a few simple steps.

First, you will need to include the authentication function in your permission_callback() method. This function will check the user’s credentials and determine if they have the necessary permissions to access the API endpoint.

Next, you will need to determine which roles or capabilities the user must have in order to access the API endpoint. This can be done using the current_user_can() function, which checks if the current user has a specific capability or role. For example, you might require that the user has the manage_options capability in order to access the endpoint.

Once you have determined that the user has the necessary permissions, you can return true from the permission_callback method to allow access to the API endpoint. If the user does not have the required permissions, you can return false to block access.

It is important to note that the authentication function and the permissions check should be performed every time the API endpoint is accessed, as the user’s permissions may change over time.

**Practical example - **

<?php
add_action( 'rest_api_init', function () {
  register_rest_route( 'myplugin/v1', '/author/(?P<id>\d+)', array(
    'methods' => 'GET',
    'callback' => 'my_awesome_func',
    'args' => array(
      'id' => array(
        'validate_callback' => 'is_numeric'
      ),
    ),
    'permission_callback' => function () {
      return current_user_can( 'manage_options' );
    }
  ) );
} );

WordPress Data-flow - Loading architectures Question Answers

Q: What is Must-use plugin or MU plugins?

Answer: Must use plugins are plugins that you won’t manage through the normal plugin admin screens. They are useful if you are building an application in which it makes no sense that end users would enable/disable parts of the application. Another use for must use plugins is a plugin that loads before all other plugins, because the normal plugins are only loaded further on in wp-settings. After loading the must use plugins, you get the earliest hook you can call: muplugins_loaded — Note that there still are no ‘normal’ plugins loaded at this point.

Q: What is Git Rebase?

Answer: Rebasing is the process of moving or combining a sequence of commits to a new base commit. Use rebase whenever you want to add changes of a base branch back to a branched out branch. Typically, you do this in feature branches whenever there’s a change in the main branch. Suppose, we’re working on feat/new-feat branch and in the meantime our develop or main branch has been updated. Then from our feat/new-feat branch, we rebase the develop branch.

Redux Question Answers

Q: What is yield in Redux saga?

Answer: Sagas are implemented as Generator functions that yield objects to the redux-saga middleware. The yielded objects are a kind of instruction to be interpreted by the middleware. When a Promise is yielded to the middleware, the middleware will suspend the Saga until the Promise completes.

Gutenberg Block Development Questions

Q: What is WordPress Gutenberg block and it’s uses?

Answer: What is WordPress Gutenberg block: From WordPress version 5.0, WordPress uses new block based approach to manage their content. They use also a new Editor to make those content manageable, that editor is Gutenberg block editor.
So, now content is made by series of multiple blocks, different block has different functionalities. Like it has paragraph block, image block, video block, column block and many of this types of block.
Uses of WordPress Gutenberg block: WordPress Gutenberg block has changed the way WordPress behaves. It actually the feature of WordPress content management system. We can now use many predefined built in blocks to make any custom content. We can extend those blocks and make various version of it and also we can also make our own block.

Here are some uses of Gutenberg blocks:

  • Basic content creation: With the Gutenberg editor, you can create basic pages and posts with text, images, and videos using blocks.
  • Advanced content creation: You can use Gutenberg blocks to create more advanced layouts that include custom designs, animations, and other functionality.
  • Custom post types: Gutenberg blocks can be used to create custom post types that have unique layouts and functionality.
  • Widgets: With Gutenberg, you can use blocks to create custom widgets that can be added to sidebars and other widgetized areas of your site.
  • Shortcodes: Gutenberg blocks can also be used to create custom shortcodes that can be added to your site’s content.

Overall, Gutenberg blocks provide a more flexible and intuitive approach to content creation in WordPress. They allow for more advanced layouts and functionality, and make it easier to create custom post types, widgets, and shortcodes.

Q: Can you develop a Custom Gutenberg block?

Answer: Yes, I can develop a custom Gutenberg block. Developing a custom gutenberg block is simple.
Steps I will follow -

  1. I will just use wp-scripts to make default setup for block development, Here is the link - https://developer.wordpress.org/block-editor/reference-guides/packages/packages-scripts/
  2. Install wp-scripts
  3. Setup wp-scripts at package.json

Q: Which Component you must have to use to make settings section for a block?

Answer: S

Q: How can you change text bold, alignment for a block or which component you should use ?

Answer: S

Q: Write a Simple block which can change a Title of the text, which will have to be from settings also

Answer: S

Software Engineering Processes Question Answers

Q: Which coding methodology you use in your organization?

Answer: We use Agile methodology to manage tasks in our organization.
Every 15 days, we **Assign a Sprint **and manage our tasks through that sprint to the developers and we try to finish that sprint.
We play Poker games to manage and assign tasks. We break down tasks in smaller parts.

Q: Which softwares do you use to manage tasks?

Answer: We use Jira to manage issues and assign tasks to software developers in our current organization. On the other hand, we also maintain everything in Github issues, cause client create issues on Github open source Repository.

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