Best Practices for Gutenberg Block Development

Why Best Practices Matter (Now More Than Ever) 

WordPress powers over 43% of the web. That means your block isn’t just running on your local dev site; it might run on hundreds of environments with unknown themes, plugins, and server setups. 

The mistakes I see most often: 

• Blocks that break after a WordPress update. 

• Inline CSS bloat that kills performance. 

• Missing accessibility features (a11y lawsuits are real). 

The goal? Build blocks that are lean, secure, and editor-friendly. Here’s how.

Start With a Clear Content Model

Before writing a single line of React or PHP, ask: 

• What does this block represent? Content or layout? 

• Which parts should be stored (saved in post content) vs. derived (calculated from settings)? 

• Does the block need global styles, custom controls, or both? 

Example: For an “Event Card” block, store title, date, and image as attributes. Don’t store pixel values or theme colors; let theme.json handle that. 

Embrace block.json

Skip messy register_block_type() calls with hardcoded settings. The block.json file is the standard now. 

Why? 

• Centralizes block metadata (title, icon, attributes). 

• Allows automatic registration with register_block_type( __DIR__ ). 

• Makes your block FSE-ready by default.

Think of block.json as the manifest for your block. 

 Use Modern JavaScript & React Practices 

Gutenberg isn’t jQuery land. It’s React. Treat it that way. 

• Write functional components with hooks (useState, useEffect, useSelect). 

• Avoid deprecated WordPress JS APIs — they change fast. 

• Tree-shake your imports. Don’t pull in the entire component library for one toggle. 

import { useState } from ‘@wordpress/element’; 
function MyBlockEdit() { 
  const [text, setText] = useState(”); 
  return <input value={text} onChange={(e) => setText(e.target.value)} />; 
}

Separate edit and save, like Church and State

The edit function is for the editor UI. The save function outputs front-end markup. Mixing them? Recipe for chaos. 

For dynamic blocks (e.g., pulling recent posts), skip save() and use render_callback in PHP. This ensures data stays fresh without users reopening the editor.

Accessibility First, Not Last 

Accessibility isn’t a “nice-to-have” — it’s part of your block’s UX. 

• Use semantic HTML. 

• Label every form field in the sidebar. 

• For interactive elements (accordion, tabs), add proper ARIA attributes and keyboard support. 

Pro tip: Test with Tab key navigation before shipping. If you can’t use your block without a mouse, fix it. 

Optimize for Responsive Design

Your block will live in unpredictable layouts. Don’t hardcode widths or margins. 

• Use CSS Grid or Flexbox with fluid units. 

• Offer layout presets like Full Width, Wide, or Content Width. 

• Respect theme.json spacing and typography. 

Bonus: If you love utility-first CSS, integrate TailwindCSS with PostCSS for Gutenberg.

Use InnerBlocks When Needed

Building a “container” block like a slider or FAQ? Don’t reinvent the wheel. 

• Use InnerBlocks to allow nesting. 

• Lock templates when structure matters (templateLock=”all”). 

• Allow specific child blocks for predictable UX. 

Example: An Accordion block with Accordion-Item child blocks. 

Performance Is Not Optional 

The editor is a React app. Heavy blocks make it slow. 

• Lazy-load inspector controls for complex settings. 

• Use useMemo to avoid recalculating expensive logic on every render. 

• Only enqueue scripts when the block is present.

Provide a Clean Editor UX

Think like a content creator, not a developer. 

• Show helpful placeholders: “Add a heading…”, “Choose an image”. 

• Group settings logically in InspectorControls panels. 

• Don’t overwhelm users with 30 options for a single block. 

Golden rule: If your block needs a tutorial video, you did it wrong. 

Test Across Versions and Devices

Blocks can break quietly after a WordPress update. Test for: 

• Backward compatibility (Gutenberg versions, Classic themes). 

• Cross-browser rendering. 

• Copy-paste scenarios (user copies content between sites). 

Automate with Jest for JS, PHPUnit for PHP, and even Playwright for e2e tests.