How To Create a WordPress Plugin From Scratch 2025

Ever wanted to build your own WordPress plugin but didn’t know where to start? Think of creating a WordPress plugin like building your own custom gadget. You know exactly what features you need, so instead of relying on pre-built tools, you design something tailored to your needs—functional, unique, and fully under your control.

Whether you’re a developer looking to add custom functionality to your site or an agency creating reusable tools for clients, learning how to create a WordPress plugin from scratch gives you the power to extend WordPress beyond its default capabilities.

In this guide, we’ll walk you through the entire process—from setting up your plugin files to adding custom features—so you can build your first WordPress plugin like a pro. Let’s get started!

Why Agencies Must Learn How to Create a Custom Plugin From Scratch

For WordPress agencies, mastering custom plugin development isn’t just an added skill—it’s a game-changer. While the WordPress ecosystem offers thousands of plugins, off-the-shelf solutions often fall short in terms of flexibility, performance, or unique client requirements. Learning to create a custom plugin from scratch allows agencies to build tailored solutions that perfectly fit their client’s needs.

Custom plugins also enhance scalability and security. Many pre-built plugins come with bloated features, unnecessary scripts, and potential vulnerabilities. By developing a plugin in-house, agencies maintain full control over the code, optimizing it for performance while ensuring strict security standards.

Moreover, offering custom plugin development sets agencies apart from competitors. Clients prefer working with agencies that can build bespoke functionalities, automate workflows, and ensure seamless integration with their existing tech stack. In short, learning how to create a WordPress plugin from scratch isn’t just beneficial—it’s an essential skill for agencies aiming for long-term success.

Pre-requisites of Creating a WordPress Plugin From Scratch

Before we start explaining how to create a WordPress Plugin from scratch, you must understand what is essential before it. So, here is our quick list:

1. Proficiency with the PHP programming language

2. Knowledge of WordPress plugin architecture and development guidelines

3. Knowledge of JavaScript, CSS, and HTML

4. Understanding of the WordPress system for action and filter hooks

5. Knowledge of WordPress APIs and database architecture

6. A development environment for your plugin’s development (Can be kept on your computer)

7. A staging environment for your plugin’s development (Can be local, or you can use a staging environment built upon InstaWP) Remember, it’s essential to have a test environment to guarantee that your plugin works as intended and presents no problems on live websites.

8. An idea (i.e., the scope of the plugin)

9. Optionally, knowledge of version control programs like Git.

10. Optionally, the ability to submit plugins to the WordPress.org repository using Subversion (SVN). A solid grasp of SVN is necessary for seamless plugin submissions because WordPress uses it as the version control system for the plugin repository.

If you are using InstaWP, you can skip maintaining a separate development environment. We are going to use this tool throughout our tutorial.

Note: If you are planning to keep this plugin for more than 7 days, either become a paid InstaWP user or use your local computer instead of this remote WordPress Sandbox environment.

How to Create a WordPress Plugin: Step By Step Guide

Creating a custom plugin isn’t rocket science. But, it certainly is a strategic approach involving multiple steps.

Step 1: Plan Your Plugin

Before you start coding for custom plugin development, you need to understand what you want to achieve with your plugin, what problem does it solve, and what features do you want to include?

This planning stage is crucial as it sets the foundation for the rest of the process. So, before you think about how to make a WordPress Plugin, here are some questions you should ask yourself:

• What problem does your plugin solve?
• Who is your target audience?
• What features do you want to include in your plugin?
• What kind of data will your plugin be storing and retrieving?
• What dependencies or plugins shall your plugin require additional resources or functionality from other plugins?

As an example, in this tutorial, I plan to explain how to create a WordPress Plugin by building a small WordPress plugin that displays a banner on all pages of the website.

I will pretend that InstaWP is carrying out a promotion and take advantage of that to build a plugin that can show a promotion message on all pages of a WordPress website. “Hot Deal. Get 50% off InstaWP Premium. Click here” is the promotion message, the plugin will be positioned in the fixed position at the top of the WordPress website.

The message will appear in red on a white background to stand out.

The above image demonstrates the outcome of the plugin development process I followed.

Step 2: Choose a Unique Name for Your Plugin

Choosing the perfect WordPress plugin name is a crucial first step in development. It should be memorable, easy to spell, and SEO-friendly to maximize visibility. Plus, it must comply with WordPress repository guidelines, meaning it shouldn’t already be in use by another plugin.

To streamline the process, consider using a plugin name generator or brainstorming keywords relevant to your plugin’s function. A search-friendly name will enhance discoverability, helping users find your plugin effortlessly.

Personally, I prefer a simple approach—I head over to WordPress.org/plugins and search for my desired name. If no similar results appear, I lock it in. No overthinking, no hassle—just a smart and strategic way to name your plugin.

Step 3: Create a Folder for Your Plugin

The next step is to create a plugin folder where every file about your plugin will be stored. You can name the folder anything you like, but it should be related to the name of your plugin.

This folder will store all the files for your plugin. so it is essential to keep it organized. Commonly the folder names follow the pattern of an acronym, a hyphen in the middle, and finally, the full name. So, for example, the folder name for the plugin “my sample plugin ” might be “msp-my-sample-plugin.”

Now, you might be wondering where to keep this folder.

Well, as told previously in this article, you can either keep it in your local WordPress Development Environment or in a Staging with InstaWP. Of course, we will use the latter method in this tutorial.

Create a folder for my sample plugin in 4 simple steps:

1. Create an account with InstaWP if you don’t have one, and create a New Site.

Now, go to the Sites page. And for the staging site you’ve created, navigate to More Actions > Tools > Code Editors.

Now, right-click on the Plugins folder (in wp-content) and select New Folder. Enter the name of your plugin folder in the alert box (let’s call our plugin “msp-my-sample-plugin”).

Alternatively, if you are using the local environment to create a custom WordPress Plugin, follow these steps:

1. Navigate to the WordPress folder on your computer.
2. While in the WordPress folder, navigate to the  “wp-content” folder and then open the “plugins” folder.
3. Create a folder and name it “msp-my-sample-plugin”.

Step 4: Create a WordPress Plugin File

The first file you need to create in the “msp-my-sample-plugin” folder is the plugin file.

The plugin file name can be anything you want, but it’s recommended to be named similarly to the plugin folder. The plugin file must be a PHP file because WordPress plugins are developed using the PHP programming language.

For example, if the plugin folder name is “msp-my-sample-plugin”, your plugin file can be named “msp-my-sample-plugin.php”. WordPress repository guidelines recommend this to maintain a clear distinction between your plugin and other plugins.

Step 5: Add the Plugin Information

WordPress will identify this plugin and use it based on the information you write in the msp-my-sample-plugin.php file. This file must contain information about your plugin, including but not limited to the plugin name, description, author, and version number.

Once you have created your plugin file, now is the right time to add information about the plugin. WordPress will recognize this information and display it in the WordPress plugin repository and the WordPress dashboard.

Let’s take the Hello Dolly plugin as our reference.

See how it looks in a Plugin repository:

The information should be located at the beginning of the entry file of the plugin file. They’re specified as comments in the entry file, like in the example below.

Let me break down some of this information.

• Plugin Name: This is the human-friendly name of your plugin. It’s important to make it specific, memorable, and unique. 
• Plugin URI: This should be the link to download your plugin.
• Description: This describes the solution your plugin offers. It should be precise and Search Engine friendly.
• Version: Users need to know the version of your plugin. You need to specify it when building your plugin and whenever you update it.
• Author: Specify the name of the plugin developer. Can be a name of an individual or organization.
• Author URI: Specify the link that would take the users to the developer’s website. Sometimes users want to reach you for support and opportunities.
• License: Specify the name of the License that governs your plugin.
• License URI: Specify the link to the license you specified above.

WordPress has got a comprehensive guide about this. Click here to learn more.

Step 6: Create the Functionality

Consider adding the code that will make the plugin work. Using PHP programming language, WordPress actions, and hooks will help you create the needed functionality.

In the code above, I created a PHP function called show_banner. Then added some CSS and HTML that would help me accomplish the goal.

Finally, I used the WordPress add_action hook called wp_head to attach this show_banner function to WordPress.

The code you write will depend on the functionality you want your plugin to offer.

Step 7: Register Activation and Deactivation Hooks

Do you want something to happen when your plugin gets activated and deactivated? The recommended solution is to implement the activation and deactivation hooks.

In my case, I want to know when my plugin is activated and when it’s deactivated so that I can estimate the number of WordPress websites using my plugin against those that are deactivated. For this, I wanted to implement an activation hook to make an API request whenever the plugin is activated and deactivated.

(1) The code in the activation hook will make a call to my external API and submit the information about the plugin activation.

(2) Whereas the code in the deactivation hook will make a call to my external API and submit information about the plugin deactivation.

The use cases for activation and deactivation hooks are endless. To learn more about WordPress actions and hooks with sample code, click here.

Step 8: Test Your Plugin

Before you release your custom plugin, you need to test it thoroughly. It would be best if you tried it on different versions of WordPress and on different themes to ensure that it works as expected. You should also test it with other plugins to ensure that it does not cause any conflicts.

Talking of testing the plugin, InstaWP is my go-to for a test/staging environment because it’s FREE, instant, and reliable. InstaWP enables me to spin up any version of WordPress in less than two minutes to have an environment that will be accessible to others so that they see what I’m working on in real-time.

In this tutorial, as we are already developing our plugin in a testing environment in InstaWP, you can begin the testing process directly.

However, if you were learning how to make a WordPress Plugin in an offline environment, follow these steps to begin testing:

• Download your plugin’s folder (from the wp-content folder in your WordPress project directory).
• Create a Staging site in InstaWP.
• Go to More Actions > Tools > Code Editor for the site you’ve created (steps are mentioned in the beginning of this article).
• Right-click on the wp-content folder and select Create Folder. Use the same name for this folder as your plugin’s folder in the offline environment.
• Right-click on this empty folder and click Upload Files.
• Add all files from your plugin folder to this online folder (in your staging site).
• Now, you can follow our testing suggestions and improve your plugin as per your assessment.

Did you create a WordPress plugin online and now want to move it to InstaWP for testing? That’s easy.

The steps are as follows:

• Install the InstaWP Connect plugin on your site (that hosts this plugin).
• Activate the plugin and create a staging in 1-click with it.
• Your staging site will appear in your InstaWP dashboard. It will have the plugin you just created.
• Now, you can follow our testing suggestions and improve your plugin as per your assessment.

Not an InstaWP user yet? Sign up now.

Step 9: Release Your Plugin

Once you have tested your plugin and are confident it works as expected, you can release it. You can submit it on the WordPress plugin repository or upload it on your website.

When submitting your plugin to the WordPress repository, follow their custom plugin development guidelines and submit your plugin for review. If it is approved, it will be available for anyone to download and use.

If you release your plugin on your website, you can make the plugin file available for download. You should also provide documentation and support for your plugin and regular updates to fix bugs and add new features. For information on how to submit your plugin to WordPress, click here.

Okay, here are the headings and paragraphs tailored for WordPress agencies and developers, focusing on best practices for custom plugin development:

Best Practices for Custom WordPress Plugin Development

For WordPress agencies and developers, building custom plugins is a core service. Delivering high-quality, robust, and maintainable plugins is crucial for client satisfaction, project efficiency, and long-term success.

Adhering to best practices isn’t just about writing code; it’s about building professional solutions that stand the test of time and complexity. This guide outlines the essential practices to elevate your WordPress plugin development.

1. Strategic Planning & Requirements Definition: Set the Stage for Success

Before diving into code, rigorous planning is paramount. For agencies, this phase is also crucial for client communication and expectation management.

• Deep Dive into Client Needs & Plugin Purpose: Clearly define the exact problem the plugin solves for the client. Go beyond surface-level requests. Understand their workflows, target audience, and desired outcomes. Solid requirements upfront prevent scope creep and costly rework later.
• Target User & Context Analysis: Consider who will interact with the plugin – site admins, content editors, end-users. Tailor the UI/UX and features to their roles and technical expertise. Understand the context of use within the WordPress ecosystem and the client’s overall website strategy.
• Competitive Analysis & Feature Scoping: Research existing plugins and WordPress core functionality. Avoid redundancy and identify opportunities to extend or improve existing solutions. Define a focused feature set for the initial version, with a roadmap for future scalability and enhancements.
• Future-Proofing & Scalability Considerations: Design the plugin architecture with future growth in mind. Modular design, well-defined APIs, and scalable database structures will prevent headaches as client needs evolve. Consider potential integrations with other systems and future WordPress updates.

2. Code Architecture & Standards: Building a Solid Foundation

Clean, consistent, and well-structured code is the hallmark of professional development. For agencies, this translates to maintainability, team collaboration, and easier onboarding for new developers.

• Embrace WordPress Coding Standards Religiously: Adherence to WordPress’s coding standards (PHP, HTML, CSS, JavaScript) is non-negotiable. This ensures code readability, reduces bugs, and fosters consistency across team projects. Integrate code linters and static analysis tools into your workflow for automated checks.
• Object-Oriented Programming (OOP) for Robustness: Leverage OOP principles to create modular, reusable, and testable code, especially for complex plugins. Classes, namespaces, and design patterns are essential tools for managing complexity and promoting code organization.
• Modular Plugin Structure for Maintainability: Break down plugin functionality into logical modules and components. Utilize folders to organize files by type (e.g., includes, admin, public, assets). A clear file structure simplifies debugging, updates, and team collaboration.
• Strategic Naming Conventions for Clarity: Prefix all functions, classes, hooks, and options with a unique identifier (e.g., agency initials + plugin name) to prevent conflicts. Consistent and descriptive naming significantly improves code readability and maintainability over time.
• Comprehensive Code Commenting for Long-Term Understanding: Invest time in writing clear and concise comments. Explain the why behind code decisions, not just the what. This is invaluable for future maintenance, team members, and even your future self revisiting the code.

3. WordPress API Mastery: Leverage the Core Power

Effective plugin development is about seamlessly integrating with WordPress, not reinventing the wheel. Agencies should prioritize using the WordPress API to its fullest extent.

• Harness the Power of WordPress Hooks (Actions & Filters): Hooks are the WordPress way to extend functionality. Master actions and filters to modify WordPress behavior and data without touching core files. This ensures compatibility and future-proofs plugins against WordPress updates.
• WordPress Database API for Secure Data Handling: Utilize the $wpdb global object for database interactions. Avoid direct SQL queries where possible and always sanitize and escape data to prevent vulnerabilities. The WordPress Database API provides secure and efficient methods for database operations.
• Settings API for Standardized Plugin Options: Implement the Settings API for plugin configuration pages. This provides a secure and consistent UI for users to manage plugin options within the WordPress admin, adhering to WordPress conventions.
• Strategic Use of Other WordPress APIs: Become proficient with other relevant APIs: Transients API for caching, HTTP API for external requests, Shortcodes API for content integration, Custom Post Types/Taxonomies for structured data, and REST API for modern integrations.
• Efficient Script & Style Enqueueing: Use wp_enqueue_script() and wp_enqueue_style() for including assets. Manage dependencies, versioning, and conditional loading for optimized performance. Enqueue scripts and styles only where they are needed to minimize bloat.

4. Security as a Core Principle: Protecting Client Sites

Security is non-negotiable. Agencies have a responsibility to deliver plugins that are not vulnerabilities waiting to be exploited.

• Rigorous Input Sanitization: Trust No User Input: Sanitize all user input – form data, URLs, database entries, etc. – before processing or storing it. Employ WordPress’s sanitization functions (sanitize_text_field(), esc_sql(), etc.) appropriately based on the data type.
• Thorough Output Escaping: Secure Display of Data: Escape all output before displaying it on the page – especially dynamic data and user-generated content. Utilize WordPress’s escaping functions (esc_html(), esc_attr(), esc_url(), etc.) based on the output context.
• Nonce Implementation for CSRF Protection: Implement nonces for all forms and AJAX requests using wp_nonce_field() and wp_verify_nonce(). This is a fundamental defense against Cross-Site Request Forgery (CSRF) attacks.
• Role-Based Access Control & Capability Checks: Enforce user permission checks (current_user_can()) before granting access to plugin features, especially in admin areas. Principle of least privilege – grant only necessary permissions to each user role.
• Prepared Statements to Prevent SQL Injection: Always use prepared statements or WordPress’s database API methods to prevent SQL injection vulnerabilities. Avoid concatenating user input directly into SQL queries – this is a critical security flaw.
• XSS Prevention: A Continuous Vigil: Maintain a constant awareness of Cross-Site Scripting (XSS) vulnerabilities. Thoroughly sanitize input and escape output to prevent malicious scripts from being injected into client sites.

5. Performance Optimization: Delivering Fast & Efficient Plugins

Performance impacts user experience and SEO. Agencies should strive for plugins that are lightweight and performant, ensuring client sites remain fast and responsive.

• Optimized Database Queries: Efficiency is Key: Write efficient database queries. Avoid redundant queries, utilize indexes, and fetch only necessary data. Use tools like Query Monitor to identify and optimize slow queries.
• Strategic Caching: Reduce Server Load: Implement caching mechanisms using WordPress’s Transients API or object caching to store and reuse frequently accessed data. Caching minimizes database load and significantly improves page load times.
• Minimize HTTP Requests: Streamline Asset Delivery: Combine CSS and JavaScript files (in production environments). Reduce external requests. Implement techniques like CSS sprites and data URIs to minimize the number of resources the browser needs to download.
• Code Profiling for Bottleneck Identification: Use profiling tools to pinpoint performance bottlenecks in your code. Optimize computationally intensive sections and identify areas for improvement.
• Lazy Loading for Non-Critical Resources: Consider lazy loading images and scripts that are not immediately visible on page load to enhance initial page load times.
• Asynchronous Task Handling for Long Processes: For time-consuming tasks, utilize Action Scheduler or similar mechanisms to run processes asynchronously in the background. This prevents blocking the main thread and ensures a smooth user experience.

6. User Experience (UX) & Accessibility: Designing for Everyone

Beyond functionality, user experience and accessibility are crucial. Agencies should deliver plugins that are intuitive, user-friendly, and accessible to all users.

• Intuitive & User-Friendly Interfaces: Design plugin settings and features with user-friendliness in mind. Follow WordPress UI conventions to ensure a consistent and familiar experience for administrators and content editors.
• Accessibility Compliance: Inclusive Design: Make plugins accessible to users with disabilities. Adhere to WCAG guidelines and use ARIA attributes where relevant. Consider screen reader compatibility, keyboard navigation, and color contrast.
• Internationalization (i18n) & Localization (l10n): Global Reach: Prepare plugins for translation into multiple languages using WordPress’s i18n functions. Create .pot files to facilitate localization and expand the plugin’s potential user base.
• Clear Error Handling & User Feedback: Transparent Communication: Provide informative error messages and user feedback. Guide users when errors occur and confirm successful actions. Clear communication enhances the user experience and reduces confusion.
• Comprehensive Documentation: Empowering Users & Developers: Create detailed documentation for both end-users (usage instructions) and developers (API documentation, extension points). A well-written README.txt file within the plugin is essential.

7. Development Workflow & Tooling: Streamlining Production

Efficient development workflows and appropriate tooling are essential for agency productivity and plugin quality.

• Mandatory Version Control with Git: Git is non-negotiable for professional development. Use version control for tracking changes, collaboration, branching, and rollbacks. Platforms like GitHub, GitLab, or Bitbucket are essential for team projects.
• Comprehensive Testing Strategies: Quality Assurance: Implement robust testing throughout the development process: Unit tests for individual components, integration tests for module interactions, and user acceptance testing (UAT) in a real WordPress environment. Automated testing should be integrated into your workflow.
• Deployment & Update Strategies: Seamless Delivery: Plan for plugin deployment and updates. Define a clear process for releasing new versions to clients. Consider automated deployment and update mechanisms for streamlined delivery.

8. Licensing & Distribution: Defining Usage Rights

Clearly define the licensing for your plugins, especially if distributing them beyond specific client projects.

• Choose an Appropriate License (GPL Compatibility): Select a license that aligns with your business model. For WordPress plugins, GPLv2 (or later) is recommended for compatibility and open-source principles.
• WordPress.org Plugin Directory Guidelines (for Public Plugins): If distributing free plugins via the WordPress.org Plugin Directory, thoroughly review and adhere to their guidelines. This ensures plugin quality, security, and compliance.

By embracing these best practices, WordPress agencies and developers can consistently deliver exceptional custom plugins: secure, performant, user-friendly, and maintainable. This commitment to quality translates directly to client satisfaction, stronger reputations, and long-term success in the WordPress ecosystem.

Conclusion

Creating a WordPress plugin can be a fun and rewarding experience. It allows you to extend the functionality of WordPress and add unique features to your website. Following the steps outlined in our WordPress advanced plugin development tutorial, you can create a plugin from scratch and make it available to others.

Just remember to plan your plugin, test it thoroughly using InstaWP, and provide documentation and support for users. Hope you have learned how to create a WordPress plugin now!