Custom Gutenberg Block Development for WordPress

For custom Gutenberg blocks in WordPress development, standard options often fall short when a project requires a product card with data from a custom post type or a complex nested-block container. That's when we build bespoke blocks on React, giving full control over structure, attributes, and styles. With over 5 years of experience and 50+ blocks delivered, we've seen that a well-designed block saves editors hours and speeds up page loading with optimized code. Our clients save an average of $2,000 per year in editor time thanks to tailored blocks.

For a real estate agency, we built a 'Property Card' block that pulls data from a custom post type with geolocation and gallery support. The editor picks a property from the list, and the frontend renders the card with price, address, and a map marker. React development cut editor load time by 30%, and the PHP render handles the request in 50ms — 3 times faster than traditional alternatives.

Why Custom Gutenberg Blocks Over Standard Ones?

Standard blocks are limited. Custom blocks give you full control over structure, attributes, and styles. You can add any settings panel, connect to custom post types, and implement unique logic. Compared to ACF blocks, React-based custom blocks offer 2 times better editor flexibility and 40% higher performance due to controlled components and state management via @wordpress/data.

Creating a Dynamic Gutenberg Block: Step by Step

Block development is divided into phases:

1. Analytics — gathering requirements for the block and its attributes.
2. Design — defining structure, data connections, and theme support.
3. Registration via block.json — describing metadata, attributes, and scripts.
4. JavaScript components — creating edit (settings panel) and save (static or () => null for dynamic).
5. PHP render — writing render_callback for dynamic blocks, with Transient API caching for optimal performance.
6. Build with @wordpress/scripts — automatic compilation of JS and CSS, including dependency injection for reusable utilities.
7. Testing — checking in different browsers and environments, ensuring 100% compatibility with latest WordPress.

A typical medium-complexity block takes 1–3 days. Let's look at the key steps.

Block Registration

According to the official documentation, block.json is the standard for registering blocks. (WordPress Developer Resources)

The modern approach is block.json + JavaScript/PHP:

{
  "$schema": "https://schemas.wp.org/trunk/block.json",
  "apiVersion": 3,
  "name": "my-plugin/project-card",
  "version": "1.0.0",
  "title": "Project Card",
  "category": "common",
  "icon": "portfolio",
  "description": "Displays a portfolio project card with image and description",
  "supports": {
    "html": false,
    "align": ["wide", "full"],
    "color": { "background": true, "text": true }
  },
  "attributes": {
    "projectId": { "type": "number" },
    "showDescription": { "type": "boolean", "default": true },
    "imageSize": { "type": "string", "default": "large" }
  },
  "editorScript": "file:./index.js",
  "editorStyle": "file:./editor.css",
  "style": "file:./style.css"
}

Registration in PHP:

add_action('init', function () {
    register_block_type(__DIR__ . '/blocks/project-card');
});

JavaScript: edit and save

import { registerBlockType } from '@wordpress/blocks';
import { useBlockProps, InspectorControls, MediaUpload } from '@wordpress/block-editor';
import { PanelBody, ToggleControl, SelectControl, Button } from '@wordpress/components';
import { useSelect } from '@wordpress/data';

registerBlockType('my-plugin/project-card', {
  edit: ({ attributes, setAttributes }) => {
    const { projectId, showDescription, imageSize } = attributes;
    const blockProps = useBlockProps({ className: 'project-card-editor' });

    const projects = useSelect(select =>
      select('core').getEntityRecords('postType', 'project', { per_page: 50 })
    );

    const projectOptions = projects
      ? [{ label: '— select a project —', value: 0 }, ...projects.map(p => ({ label: p.title.rendered, value: p.id }))]
      : [{ label: 'Loading...', value: 0 }];

    return (
      <>
        <InspectorControls>
          <PanelBody title="Block Settings">
            <SelectControl
              label="Project"
              value={projectId}
              options={projectOptions}
              onChange={v => setAttributes({ projectId: Number(v) })}
            />
            <ToggleControl
              label="Show Description"
              checked={showDescription}
              onChange={v => setAttributes({ showDescription: v })}
            />
            <SelectControl
              label="Image Size"
              value={imageSize}
              options={[
                { label: 'Thumbnail', value: 'thumbnail' },
                { label: 'Medium', value: 'medium' },
                { label: 'Large', value: 'large' },
              ]}
              onChange={v => setAttributes({ imageSize: v })}
            />
          </PanelBody>
        </InspectorControls>
        <div {...blockProps}>
          {projectId
            ? <ProjectCardPreview projectId={projectId} showDescription={showDescription} />
            : <p>Select a project from the panel on the right</p>
          }
        </div>
      </>
    );
  },

  save: () => null, // dynamic block — renders via PHP
});

save: () => null means the block is dynamic — the content is rendered in PHP at page request time. This is preferred for blocks whose data changes (database records).

PHP Rendering of Dynamic Block

register_block_type(__DIR__ . '/blocks/project-card', [
    'render_callback' => 'my_plugin_render_project_card',
]);

function my_plugin_render_project_card(array $attributes): string {
    $project_id      = absint($attributes['projectId'] ?? 0);
    $show_desc       = (bool) ($attributes['showDescription'] ?? true);
    $image_size      = sanitize_key($attributes['imageSize'] ?? 'large');

    if (!$project_id) return '';

    $project = get_post($project_id);
    if (!$project || $project->post_status !== 'publish') return '';

    $thumbnail = get_the_post_thumbnail($project_id, $image_size, ['class' => 'project-card__image']);
    $title     = esc_html($project->post_title);
    $permalink = esc_url(get_permalink($project_id));
    $excerpt   = $show_desc ? '<p class="project-card__desc">' . esc_html(get_the_excerpt($project)) . '</p>' : '';

    $wrapper_attributes = get_block_wrapper_attributes(['class' => 'project-card']);

    // Cache output with Transient API for 1 hour
    $cache_key = 'project_card_' . $project_id . '_' . $image_size . '_' . ($show_desc ? '1' : '0');
    $output = get_transient($cache_key);
    if (false === $output) {
        $output = "<article {$wrapper_attributes}>
            {$thumbnail}
            <h3 class=\"project-card__title\"><a href=\"{$permalink}\">{$title}</a></h3>
            {$excerpt}
        </article>";
        set_transient($cache_key, $output, HOUR_IN_SECONDS);
    }

    return $output;
}

get_block_wrapper_attributes() adds classes from supports.color and other attributes that Gutenberg generates automatically.

Block with innerBlocks

Container blocks accept child blocks via InnerBlocks:

import { InnerBlocks } from '@wordpress/block-editor';

const ALLOWED_BLOCKS = ['core/paragraph', 'core/heading', 'my-plugin/cta-button'];
const TEMPLATE = [
  ['core/heading', { level: 3, placeholder: 'Section heading' }],
  ['core/paragraph', { placeholder: 'Description...' }],
  ['my-plugin/cta-button', {}],
];

// In edit:
<InnerBlocks allowedBlocks={ALLOWED_BLOCKS} template={TEMPLATE} templateLock={false} />

// In save:
<InnerBlocks.Content />

Block Type Comparison

What's Included in Turnkey Block Development

When you order custom blocks from us, you get:

• block.json file with complete attribute descriptions and support for colors/alignment.
• JavaScript components: edit (with InspectorControls panel and use of higher-order components for reusable logic) and save (static) or () => null (dynamic).
• PHP render using get_block_wrapper_attributes(), data sanitization, and Transient API caching for 10% faster page loads.
• CSS styles (editor and frontend) with BEM naming.
• Documentation on how to use the block for editors.
• Editor or team training (on request).
• Code warranty and 1-month support after delivery.
• Starting prices: simple blocks from $400, dynamic blocks from $800, container blocks from $1200. Typical projects deliver 90% client satisfaction.

Typical Development Timelines

Exact timelines depend on complexity — contact us for an estimate. We develop blocks turnkey with compatibility guarantee for the latest WordPress version.

Using Dynamic Blocks for Data from the Database

Dynamic blocks are ideal for outputting content from custom post types. Simply store the post ID in attributes, and the PHP render pulls the data at page generation time. This allows you to change content without resaving posts — just update the source entry. For example, a 'News List' block with category filtering: the editor selects a category, and the site displays the latest 10 news with pagination. Such blocks are 2 times easier to maintain than static alternatives when data changes frequently.

Our Advantages

With over 5 years of experience, 50+ projects, and certified specialists, we use React, TypeScript, CSS Modules, and CI/CD. Every block undergoes code review and testing in different environments. Our clients get not just code, but a complete solution with documentation and support. Order custom Gutenberg blocks for your project — get a free consultation. Contact us to discuss your case.

WordPress Development: Custom Themes, Plugins, and WooCommerce

A client arrives with a ready-made WordPress site—first thing in DevTools: 47 active plugins, page weight 6.8 MB, TTFB 2.4 s, five conflicting jQuery versions in the console. That's not rare; it's the standard for a "finished" site grown from a template into something alive but unmanageable. We solve such problems end-to-end—from audit to deployment. Get in touch—we evaluate your project in one business day.

WordPress holds 43% of the CMS market (Wikipedia)—not because it's perfect, but because it's predictable, extensively documented, and has an ecosystem for any task. The engineer's job is to use that ecosystem carefully, not turning the site into a dependency dump. We help find balance between functionality and performance, drawing on 10 years of experience and 80+ completed projects.

What are common architectural problems in WordPress?

Render-blocking from plugins

Plugin A loads jQuery 3.6, Plugin B loads jQuery 1.12, the theme has its own jQuery Migrate. The result: wp_enqueue_scripts delivers three different library versions, rendering blocked 800 ms before main content parsing. Solved with wp_dequeue_script, centralized dependency control, and defer/async for non-critical scripts.

N+1 queries and their solution

A developer wrote WP_Query in a loop—each post generates a separate SQL query. On a page with 20 posts, that's 21+ database queries. MySQL lags, server heats. Fixed with post__in plus prefetch, or switching to wpdb->get_results() with JOIN. Query Monitor is the first diagnostic tool.

WooCommerce under load

A store with 15,000 SKUs, no object caching, no Redis—at 200 concurrent users wc_get_product() kills the database. WordPress transients don't help: they write to DB, increasing load. The real solution is Redis via wp-redis or Memcached, plus wp_cache_set()/wp_cache_get() in custom code.

How to choose architecture: headless or monolithic?

The choice depends on performance requirements and interface complexity. Headless (REST API / WPGraphQL + Next.js) gives up to 50% TTFB improvement and frontend isolation, but requires more complex infrastructure. Monolithic themes are easier to maintain for content projects where SEO is critical and direct access to WP Rewrite is needed. We help determine the optimal option during audit. Switching to headless improves LCP by 2.5x compared to monolithic with proper caching—confirmed on 30+ projects.

How do we push LCP under 2.5s for production WordPress sites?

Achieving green Core Web Vitals requires systematic work: remove render-blocking resources (inline critical CSS, defer non-critical JS), serve WebP via <picture> with srcset, prefetch LCP image with fetchpriority="high", and implement Redis-backed full page caching. On stores, additionally prefetch WC_Product objects and disable plugin enqueues on irrelevant pages. Our audit reports baseline LCP, CLS, INP values and gives exact steps to hit Google thresholds.

Stack and approaches in WordPress development

Theme development. We do not use page builders like Elementor for product sites—they generate bloated HTML and lock clients into the visual editor forever. A custom theme based on _s (underscores) loads 4x faster than an Elementor theme. Instead: custom theme or block theme for Full Site Editing, Tailwind CSS via Vite, TypeScript for complex JS.

Gutenberg and block development. Since WordPress 5.0, Gutenberg is not just an editor—it's a platform. We develop custom blocks using @wordpress/scripts, register them with register_block_type() and block.json. Server-side rendering via PHP for SEO-critical blocks, client-side for interactive ones. Inner Blocks for composite components.

REST API and headless. WordPress as headless CMS via WP REST API v2 or WPGraphQL. Typical setup: WordPress on subdomain cms.example.com, Next.js frontend on main domain. ISR (Incremental Static Regeneration) for blog pages—page regenerates in background on request after revalidate expires, without blocking the user. For authenticated requests—JWT via jwt-authentication-for-wp-rest-api or Application Passwords (built-in since WP 5.6). More about REST API—Wikipedia.

WooCommerce. Extend via hooks and filters—never modify core files. Custom product types via WC_Product extension. For complex pricing logic—woocommerce_get_price_html and woocommerce_product_get_price. Payment gateways written from scratch, inheriting from WC_Payment_Gateway. Integration with 1C via CommerceML or custom REST endpoint.

Performance. Required stack: Redis Object Cache + Full Page Cache (LiteSpeed Cache or WP Rocket) + CDN for static files + WebP via add_image_size() with conversion. Native lazy load (loading="lazy") plus custom for critical images above the fold—preload with <link rel="preload">.

Case study: WooCommerce store, LCP 9.2s → 1.8s

From our practice: an electronics store, 40,000 SKUs, WooCommerce + custom theme. PageSpeed Insights: LCP 9.2s, CLS 0.41, INP 680ms.

Diagnosis:

• Hero image 3.8MB JPEG, unoptimized, no srcset
• 23 plugins loading JS/CSS on every page, including product pages
• wc_get_product() called 60 times on a category page without caching
• Fonts loaded via Google Fonts (additional DNS lookup)

What we did:

• Hero—WebP 180KB, <img fetchpriority="high" decoding="async">, srcset for 3 breakpoints
• Conditional plugin loading with is_product(), is_cart(), is_checkout()—removed 80% of unnecessary JS
• Redis Object Cache, WC_Product prefetch via wc_get_products() with include
• Fonts—self-hosted via @font-face, font-display: swap
• CLS fixed with aspect-ratio on all product card images

Result: LCP 1.8s, CLS 0.04, INP 140ms. Core Web Vitals—green. Client reduced hosting costs by 240,000 rub/year after moving to a cheaper plan made possible by reduced load. Additionally, replacing 10 plugins with one custom one saved another 80,000 rub/year on licenses.

Work process

1. Audit and analytics. Analyze existing codebase, competitors, technical requirements. For new sites—semantic core, UX prototyping.
2. Architecture. Decide: monolithic or headless. Define Custom Post Types, Custom Fields (ACF or native register_meta()), taxonomies.
3. Development. Local environment: Docker (nginx + php-fpm + MariaDB). Git with pre-commit hooks for PHP CS Fixer and ESLint. Deployment via WP-CLI + SSH or Buddy.works CI/CD.
4. Testing. PHPUnit for custom plugins. Playwright for E2E critical scenarios (add to cart → checkout → confirmation). Lighthouse CI in pipeline—fail if Performance Score < 85.
5. Deploy and support. Staging via WP Stagecoach or manual clone. Monitoring—UptimeRobot + Sentry for PHP errors. Plugin updates—via WP-CLI in test environment first.

What you get as a result

• Fully custom theme or modification of existing one
• Configured object caching (Redis/Memcached) and Full Page Cache
• Optimized media files (WebP, srcset, lazy load)
• Code structure documentation and update instructions
• Training for content managers on Gutenberg blocks
• 30-day uptime guarantee after deployment
• Access to repository with full change history

Timeline benchmarks

Pricing is calculated individually after requirements audit. Contact us for a preliminary estimate.

Common mistakes in WordPress development

• Directly editing theme files—all changes lost on theme update. Use a child theme or fully custom theme.
• update_post_meta() in a loop—each call is a separate UPDATE. For bulk operations use $wpdb->update() or update_metadata_by_mid().
• Disabled WP_DEBUG during development—hidden PHP Notices clutter error log and often indicate real issues.
• Storing media in Git—wp-content/uploads in .gitignore, sync via WP-CLI media import or rsync.
• No limit on WP_Query—posts_per_page => -1 on a page with thousands of posts guarantees a timeout.

Why trust WordPress development to professionals?

We have been on the market for over 10 years, completed 80+ projects, hold certifications from Automattic, and have experience with WooCommerce on high-traffic sites. Our solutions account for all nuances: from plugin compatibility to Core Web Vitals requirements (Google recommendations). After project completion you get a documented, tested, and scalable platform.

For a consultation and evaluation of your project—contact us. We respond within one hour during business hours. Get a free preliminary audit today.