WordPress Gutenberg Block Development with React & PHP

Gutenberg uses React, but not always in the way you expect. This lesson covers the @wordpress/element abstraction, why WordPress maintains its own React wrapper, and what that means for your code.

We write your first custom block from scratch. You will define block metadata, create the edit and save components, and see the block appear in the editor inserter.

The edit component is what users interact with. We build an editable block using RichText, understand how JSX maps to the rendered DOM, and wire up attribute saving.

Save components define the HTML saved to the database. We cover how to write clean, accessible save markup, when to return null, and how WordPress uses it for front-end rendering.

A deep look at the attribute system: types, sources, selectors, and default values. We also cover useBlockProps() and why every block component needs it for proper editor behavior.

Not everything belongs in block attributes. We use useState for UI-only state, useEffect for side effects, and discuss when each approach is the right choice for your block.

A practical exercise where you build a testimonial block with multiple text fields, an image, and a rating. This reinforces everything from the previous lessons in a single, realistic project.

Blocks fail validation more often than you think. We cover the validation process, common causes of block invalidation, and a systematic approach to debugging block issues.

Sometimes you need third-party React libraries. We cover how to import external packages, manage dependencies with npm, and handle the quirks of loading them inside the editor.

You build a feature card block with an icon selector, heading, description text, and a call-to-action button. This lesson cements the block development workflow through repetition.

Static save markup is not always enough. We cover the scenarios where PHP server-side rendering is necessary and the trade-offs between static and dynamic block approaches.

The PHP-side registration mirrors the JavaScript side. We set up register_block_type() in PHP, configure render_callback, and load assets properly through block.json metadata.

We convert one of our earlier blocks to dynamic rendering. The PHP callback receives block attributes and renders server-generated HTML, including data from the WordPress database.

Blocks often need front-end CSS and JavaScript. We cover viewScript, viewStyle in block.json, conditional loading, and how to keep front-end assets minimal and fast.

We use @wordpress/api-fetch to pull data from the WordPress REST API into our React block components. Includes loading states, error handling, and caching considerations.

Sometimes the default REST API endpoints are not enough. We register custom routes in PHP, handle permissions, and connect them to our block's React components.

Blocks interact with the broader WordPress hook system. We explore how to use PHP filters to customize block output, add wrapper elements, and modify rendering context.

A substantial project: build a block that queries posts with custom parameters set in the editor sidebar, renders results server-side, and supports pagination. Combines every PHP concept so far.

A single block in a plugin is simple. Multiple blocks with shared code require structure. We set up a plugin with shared components, utilities, and a clear separation between blocks.

We extract reusable UI components: color pickers, URL inputs, media uploaders, and icon selectors. These shared pieces reduce duplication and keep your library consistent.

InnerBlocks lets blocks contain other blocks. We build a section container and a column layout block, covering allowedBlocks, templateLock, and useInnerBlocksProps.

Templates define pre-set inner block arrangements. We create block templates for common layouts and discuss when to lock templates versus letting users modify them freely.

The block sidebar is prime real estate for settings. We build custom panel controls, use TextControl, SelectControl, ToggleControl, and organize them into logical panels.

We add toolbar buttons for text alignment, media selection, and custom actions. Covers BlockControls, AlignmentToolbar, and building your own toolbar group.

Styles change appearance without changing functionality. Variations create preset configurations. Transforms convert between block types. We implement all three in our library.

Block patterns are pre-designed arrangements of blocks. We register custom patterns that use our library blocks, giving users ready-made layouts they can drop in and edit.

The data store is Gutenberg's Redux-like state management. We cover stores, selectors, actions, and resolvers, then use them to share state across blocks that need to communicate.

We wire up interconnected blocks that read from and write to the same data store. Practical examples include a settings block that controls the behavior of a display block.

WordPress provides built-in support for color, font size, spacing, and more. We configure these in block.json and customize them with PHP filters for brand-specific palettes.

A capstone for this section: build a hero block with InnerBlocks, background image/color controls, text alignment toolbar, responsive spacing, and custom block styles.

An overview of what to test and why. We cover the testing pyramid for block development: unit tests for React logic, integration tests for block registration, and PHPUnit for PHP rendering.

We set up Jest with @wordpress/scripts, write tests for edit and save components, mock WordPress dependencies, and test attribute handling and user interactions.

Test your PHP render_callback functions in isolation. We set up PHPUnit for WordPress, write tests that verify rendered HTML, and test custom REST API endpoints.

We write end-to-end tests that open the editor, insert blocks, change settings, and verify the saved output. Covers the @wordpress/e2e-test-utils-playwright package.

Large block libraries can slow down the editor. We implement dynamic imports, lazy-load block components, and use webpack code splitting to keep initial load times short.

Blocks re-render frequently in the editor. We use React.memo, useMemo, and useCallback strategically to prevent unnecessary renders without over-optimizing.

Your blocks must be usable by everyone. We cover ARIA labels, keyboard navigation, focus management, screen reader announcements, and testing with automated accessibility tools.

Sanitizing user input in attributes, escaping output in PHP render callbacks, validating REST API requests, and preventing XSS in custom block controls.

We prepare the plugin for distribution: proper file headers, readme.txt, asset optimization, uninstall cleanup, and submission checklist for the WordPress plugin directory.

If other developers will use your blocks as a dependency, we cover npm publishing, semantic versioning for block libraries, and managing breaking changes in the block API.

WordPress is moving toward the Interactivity API for front-end interactivity. We cover what it does, how it differs from attaching custom scripts, and when to adopt it.

Block development evolves with each WordPress release. We discuss how to track changes, handle deprecations, migrate blocks to newer API versions, and stay informed without constant effort.

You bring everything together. Build a block library plugin with at least five interconnected blocks, dynamic rendering, shared components, tests, and deploy it to a live WordPress site.