Building Custom WordPress Blocks with React: Because Gutenberg Won’t Build Itself
I’m going to be honest with you. When WordPress announced Gutenberg was built with React JS, I laughed. Not a “haha that’s funny” laugh, but more of a “oh no, what have they done” nervous chuckle. WordPress, the PHP dinosaur that powers 43% of the internet, suddenly wanted us to write JavaScript like it was 2023.
Plot twist: it actually works. And once you stop fighting it, building custom blocks is genuinely fun.
Why Custom Blocks? Why Now?
Here’s the thing about the default Gutenberg blocks. They’re fine. Perfectly adequate. Like gas station coffee—it’ll get you through the morning, but you’re not excited about it.
Your clients, however? They want espresso. They want blocks that match their brand, handle their specific content types, and don’t require them to hire you every time they need to update a testimonial. Custom blocks deliver exactly that.
I spent years building Advanced Custom Fields layouts. Flexible content, repeater fields, the whole circus. It worked, sure. But explaining to clients why they couldn’t see their changes in the editor? Exhausting.
The Basic Anatomy of a WordPress Block
Every custom block needs two things: a registration file and some React magic. That’s it. Well, okay, that’s a simplification. You also need webpack, npm, a working knowledge of JSX, and probably a therapist for when your build fails at 2 AM.
Let me break down what you’re actually building:
- block.json – Your block’s ID card. Name, description, category, all that metadata.
- edit.js – What users see in the editor. This is where your React JS skills shine.
- save.js – What gets saved to the database and rendered on the frontend.
- style.scss – Because even blocks need to look pretty.
The edit and save functions are where coding gets interesting. They’re essentially React components with superpowers.
Setting Up Your Development Environment
WordPress actually did something smart here. The @wordpress/create-block package scaffolds everything for you. Run one command, get a fully functional block with hot reloading. Revolutionary? No. But incredibly helpful when you’re staring at a blank terminal wondering where to start.
Here’s my hot take: don’t skip the scaffolding step to “learn how it works.” I tried that. Spent four hours configuring webpack before realizing the official tool did it better in thirty seconds.
Once your environment is running, you’ll notice something familiar if you’ve worked with React before. useState, useEffect, all your old friends are here. WordPress just wraps them in their own packages like @wordpress/element.
The Edit Function: Where the Magic Happens
Your edit function is basically a React component that receives props. The most important ones? attributes and setAttributes. If you’ve ever used useState, this will feel natural. Attributes hold your block’s data, setAttributes updates it.
Want to add an image? WordPress gives you MediaUpload. Need rich text? RichText component. Color picker? PanelColorSettings. The component library is surprisingly robust once you know where to look.
Here’s where web design meets functionality. You can style your editor preview to match your frontend exactly. No more “publish and pray” workflows where clients guess what their content will look like.
Common Gotchas That’ll Waste Your Afternoon
I’ve made every mistake so you don’t have to. Well, you probably still will. But at least you’ll know you’re not alone.
First gotcha: the save function must be pure. No useState, no useEffect, no API calls. It renders once and creates static HTML. This confused me for an embarrassing amount of time. Why couldn’t I fetch data in save()? Because save() runs once when you hit publish, not on every page load.
Second gotcha: if you change your save function’s output after blocks are already published, WordPress throws a block validation error. Your old blocks literally break. The solution? Either migrate your blocks programmatically or use render_callback for dynamic blocks.
Third gotcha: your images are probably too big. This isn’t specific to blocks, but I’ve seen so many custom blocks that let users upload 4MB PNGs without any optimization. Build in size limits. Your future self will thank you.
Dynamic vs Static Blocks: Choose Wisely
Static blocks save their HTML directly to the post content. Fast, simple, cacheable. Perfect for testimonials, call-to-action boxes, or anything that doesn’t need real-time data.
Dynamic blocks use PHP to render on each page load. Need to pull the latest posts? Show user-specific content? Query an API? Dynamic blocks are your friend.
The performance difference matters. Static blocks are basically free. Dynamic blocks hit your server every request—though if you’ve set up Redis object caching, you can mitigate that pain significantly.
Taking It Further: Block Patterns and Variations
Once you’ve got custom blocks working, patterns are the next level. Think of them as pre-configured arrangements of blocks. Build once, reuse everywhere.
Block variations are similar but different. Same block, different defaults. A “testimonial” block variation might have a quote icon enabled by default, while a “review” variation includes star ratings.
This is where your javascript skills really pay off. You’re not just building blocks anymore—you’re building a content system.
The React Server Components Question
I know what you’re thinking. “If WordPress uses React, can I use React Server Components?”
Short answer: not yet. WordPress’s JavaScript infrastructure predates RSC, and the Gutenberg team hasn’t announced any plans to integrate them. You’re working with good old client-side React here.
That said, understanding Server Components helps you appreciate why WordPress chose dynamic blocks with PHP rendering. Same concept, different implementation.
Should You Even Bother?
Look, custom WordPress blocks aren’t for everyone. If your site has five pages and a contact form, you’re overengineering. Stick with the defaults.
But if you’re building for clients who need consistent, branded content types? If you’re maintaining sites where content editors shouldn’t need developer handholding? If you actually enjoy wordpress dev and want to level up?
Custom blocks are worth the learning curve. Steep at first, then suddenly everything clicks. The editor becomes a genuine design tool instead of a glorified text area.
I’ve shipped maybe thirty custom blocks across various projects now. Some were overkill. Most became the features clients actually used every day. That’s the real test—not whether you can build it, but whether it makes someone’s workflow better.
Now go scaffold a block. Break something. Fix it. That’s the only way this stuff sticks.