As WordPress projects grow in complexity, organizing your codebase becomes essential. Whether you’re building a plugin, theme, or block library, a clean and scalable architecture makes development faster, onboarding easier, and long-term maintenance far less painful. In Refactoring the Multi-Block Plugin: Build Smarter, Register Cleaner, Scale Easier, I walked through setting up a flexible structure for managing multiple static, dynamic, and interactive blocks within a single plugin. That setup serves as the foundation for this guide. Here, we’ll take things a step further by introducing PHP namespaces, autoloading with Composer, and enforcing consistent coding standards across JavaScript, CSS, and PHP. These aren’t just best practices — they’re practical steps for maintaining quality and scaling your code as your project grows. We’ll walk through: Setting up PSR-4 autoloading with Composer Structuring plugin functionality into reusable, purpose-driven classes Enforcing consistent styles with automated linting and formatting tools This workflow is flexible enough for solo developers, yet robust enough to support team collaboration on large-scale projects. Pre-requisites This article builds on Refining a Multi-Block Plugin. If you’ve already followed that guide to scaffold a plugin with static, dynamic, and interactive blocks, you’re ready to dive into this next step. Prefer to skip the setup? The full plugin built in this article is available on GitHub with each section of this article is represented in a branch. Want to follow along but don’t want to build the multi-block start point? You can clone the multi-block repo, run npm install and start from there. Either approach will give you a ready-to-use starting point with namespacing, Composer autoloading, and linting already wired up. Namespacing and classes As the plugin grows, it’s important to keep the code organized and easy to manage. I use PHP namespaces and split functionality into classes so each part of the plugin has a clear purpose. This helps avoid naming conflicts and makes the codebase easier to scale and maintain. Composer and autoloading To streamline how classes are loaded, I use Composer with PSR-4 autoloading. This means I don’t need to manually include files, Composer automatically loads classes based on the namespace and folder structure I define. In this setup, I use the namespace Advanced_Multi_Block to group all plugin-related classes. This acts like a prefix, helping avoid naming conflicts and keeping everything contained within the plugin’s scope. I start by creating a composer.json file in the plugin root and adding the following: { "name": "multi-block/namespacing-coding-standards", "description": "An advanced multi block plugin with custom functionality.", "type": "wordpress-plugin", "license": "GPL-2.0-or-later", "autoload": { "psr-4": { "Advanced_Multi_Block\\": "Functions/" } } } Then I run: composer install . This generates the vendor folder and an autoloader that I can include in the main plugin file. Files and classes With autoloading in place, I organize all class-based PHP files into a Functions folder inside the plugin. This keeps everything in one place and makes it easier to manage as the plugin grows. Each class handles a specific piece of functionality and is namespaced under Advanced_Multi_Block . This structure helps keep responsibilities clear and avoids naming conflicts across the codebase. Plugin Paths This class provides helper methods for getting the plugin’s base path and URL. I use it throughout the plugin to avoid repeating logic or relying on hardcoded values. Inside the Functions directory I create Plugin_Paths.php and paste in the following code: A custom set of rules to check for a WordPress plugin . /build/ /node_modules/ /vendor/ src/blocks-manifest.php build/*.asset.php This is a starting point based on the official WordPress standards. I’d recommend reviewing the full WPCS documentation if you want to customize it further. Next, I update my composer.json file to install the required dependencies and define scripts for linting and formatting: { "name": "wp-dev-blog/refactor-multi-block-plugin", "description": "An advanced multi block plugin with custom functionality.", "type": "wordpress-plugin", "license": "GPL-2.0-or-later", "autoload": { "psr-4": { "Advanced_Multi_Block\\": "Functions/" } }, "require-dev": { "wp-coding-standards/wpcs": "^3.1" }, "config": { "allow-plugins": { "dealerdirect/phpcodesniffer-composer-installer": true } }, "scripts": { "format": "./vendor/bin/phpcbf --report-summary --report-source || true", "lint": "./vendor/bin/phpcs" } } Then I run: composer update to install the new packages. In package.json , I add the following scripts to lint and fix PHP files. These replace any existing lint:php or format:php entries: "lint:php": "composer run lint", "format:php": "phpcbf --standard=phpcs.xml.dist -v", I can now run npm run lint:php or npm run format:php to lint and fix PHP files. Global commands To keep all linting commands consistent across environments, I add the following to package.json : "lint": "npm run lint:js && npm run lint:php && npm run lint:css", "format": "npm run format:js && npm run format:php && npm run format:css", Autoloading with Composer With Composer’s PSR-4 autoloading defined in composer.json , you don’t need manual require statements for your classes. The main plugin file loads the generated vendor/autoload.php , and Composer handles the rest. Whenever you add, move, or rename classes, run: composer dump-autoload This step refreshes the class map so new or updated files are discoverable. It’s an easy but important habit that prevents “class not found” errors and keeps your plugin’s structure in sync with your namespaces. Conclusion By adding namespacing, Composer autoloading, and clear coding standards, you create a foundation that’s built to last. Your code becomes easier to reason about, test, and extend — and it stays that way as your plugin or theme grows. Each component of this setup plays a part: Namespaces and classes separate concerns and reduce conflicts separate concerns and reduce conflicts Composer autoloading eliminates boilerplate and scales effortlessly eliminates boilerplate and scales effortlessly Linting and formatting tools keep your code clean and consistent across the entire stack This approach isn’t just about polish, it’s about building with confidence and avoiding slowdowns as your codebase evolves. Whether you’re building for clients, teams, or yourself, these practices help ensure the project remains maintainable, performant, and collaborative. As always, feedback is welcome. If you have suggestions, questions, or want to share how you’re structuring your own projects, I’d love to hear from you. Props to @meszarosrob and @milana_cap for reviewing this article and offering feedback.