Title: Guardrail Blocks Author: BreonWilliams Published: July 13, 2026 Last modified: October 2, 2026 --- Search plugins ![](https://ps.w.org/guardrail-blocks/assets/banner-772x250.png?rev=3725373) ![](https://ps.w.org/guardrail-blocks/assets/icon.svg?rev=3725373) # Guardrail Blocks By [BreonWilliams](https://profiles.wordpress.org/breonwilliams/) [Download](https://downloads.wordpress.org/plugin/guardrail-blocks.0.1.2.zip) * [Details](https://li.wordpress.org/plugins/guardrail-blocks/#description) * [Reviews](https://li.wordpress.org/plugins/guardrail-blocks/#reviews) * [Development](https://li.wordpress.org/plugins/guardrail-blocks/#developers) [Support](https://wordpress.org/support/plugin/guardrail-blocks/) ## Description Most accessibility failures on WordPress sites are authoring failures: a brand color that doesn’t meet WCAG contrast, a heading hierarchy scrambled by reordering, an accordion built from divs with no keyboard support. They look fine in the editor and fail the audit later. Guardrail Blocks takes a different approach: instead of _offering_ accessible options, its blocks make the failure impossible to author — and re-verify everything on every page view. #### The guarantees * **WCAG-safe color contrast** — Button backgrounds come only from your theme’s palette (plus any custom colors added in Global Styles), and the most readable text color is chosen automatically (the live ratio is shown in the sidebar, e. g. “Contrast 8.36:1 — AA ✓”). The pairing is re-validated server-side on every page view against your theme’s _current_ palette, so switching themes or changing brand colors can never leave a failing button behind. * **Unbreakable heading hierarchy** — There is no heading level control anywhere. An Accessible Heading derives its level (H2–H6) from how Accessible Sections are nested, and re-derives it when you reorder, nest, or un-nest — the document outline stays valid by construction. Card titles and accordion headers participate too, always one level below their section’s heading. * **Correct interactive semantics** — The Accordion ships the full WAI-ARIA disclosure pattern: real buttons inside correctly-leveled headings, `aria-expanded`/`aria- controls` wiring, Enter/Space toggling, arrow-key navigation between headers, and content that stays reachable without JavaScript. * **Performance-correct media** — The Media Figure renders through core’s responsive- image pipeline with explicit dimensions (no layout shift), `srcset`/`sizes`, a hero toggle for `fetchpriority="high"` (better LCP) vs. lazy loading, and alt text enforcement with editor warnings. #### The blocks Accessible Section, Accessible Heading, Accessible Button, Card + Card Grid, Accessible Accordion, Notice (info/success/warning/error with correct ARIA roles), Media Figure, and a Table of Contents that is generated from the page’s real outline on every view — it can never go stale. #### Safety nets * The **Outline Checker** panel (in the page sidebar) watches the whole document— including core Heading blocks — and flags skipped levels and extra H1s with one- click block selection. * Everything inherits your theme’s colors, spacing, and typography via `theme.json`. Nothing fights your design. * The plugin makes **zero external requests** and collects no data. #### Source code & development The compiled block scripts in `build/` are generated with @wordpress/scripts (webpack). The complete, human-readable source code is included with this plugin in the `src/` directory (TypeScript and SCSS, one folder per block). To rebuild `build/` from it: `npm install && npm run build` (Node 22; `package.json` and `tsconfig.json` are included). Development happens publicly at https://github.com/breonwilliams/guardrail-blocks, which also carries the full test suite (Jest, PHPUnit, Playwright) and CI. ## Screenshots [⌊The Starter Brochure Page pattern: hero, feature cards, FAQ, and call-to-action with a guaranteed-valid heading outline.⌉⌊The Starter Brochure Page pattern: hero, feature cards, FAQ, and call-to-action with a guaranteed-valid heading outline.⌉[ The Starter Brochure Page pattern: hero, feature cards, FAQ, and call-to-action with a guaranteed-valid heading outline. [⌊Contrast enforcement in the editor: pick a background from the theme palette and the readable text color is chosen automatically, with the live WCAG ratio shown.⌉⌊ Contrast enforcement in the editor: pick a background from the theme palette and the readable text color is chosen automatically, with the live WCAG ratio shown.⌉[ Contrast enforcement in the editor: pick a background from the theme palette and the readable text color is chosen automatically, with the live WCAG ratio shown. [⌊The Outline Checker panel lists every heading — including core Heading blocks — and flags outline problems.⌉⌊The Outline Checker panel lists every heading — including core Heading blocks — and flags outline problems.⌉[ The Outline Checker panel lists every heading — including core Heading blocks — and flags outline problems. [⌊The Accessible Accordion on the front end: real buttons, correct ARIA, full keyboard support.⌉⌊The Accessible Accordion on the front end: real buttons, correct ARIA, full keyboard support.⌉[ The Accessible Accordion on the front end: real buttons, correct ARIA, full keyboard support. ## Blocks This plugin provides 10 blocks. * Notice A callout with the correct semantic role built in — info, success, warning, or error — announced properly by screen readers and never relying on color alone. * Card Grid A responsive grid of cards. Columns adapt to the available space automatically — no breakpoints to configure, nothing to break. * Accessible Section A content section that manages heading structure for you: any Accessible Heading inside renders at the correct level based on how sections are nested — reordering can never break your document outline. * Accessible Accordion Expandable content panels with correct disclosure semantics and full keyboard support built in — Enter/Space to toggle, arrow keys to move between headers, screen-reader announcements for free. * Table of Contents A table of contents generated from the page's real heading outline on every view — reorder your sections and it stays correct, automatically. * Accessible Button A call-to-action button whose colors are always WCAG-safe: pick a background from your theme palette and the most readable text color is chosen for you — re-checked on every page view. * Accessible Heading A heading whose level (H2–H6) is set automatically from where it sits in your section structure. You write the words; the correct level is guaranteed — even after reordering. * Media Figure An image with performance-correct markup guaranteed: responsive sizes, explicit dimensions (no layout shift), smart loading priority, and enforced alt text. * Accordion Item One expandable panel inside an Accessible Accordion. The header is a real button inside a correctly-leveled heading; the panel is a labeled region. * Card One card in a Card Grid. Its title is an Accessible Heading, so card titles automatically join the page outline at the correct level. ## FAQ ### Does this replace core blocks? No. It’s a focused set that mixes freely with core blocks — use core paragraphs, images, and columns as usual. The Outline Checker even watches headings you author with the core Heading block. ### What happens to an uncolored button? It inherits your theme’s own button styling (the same `wp-element-button` mechanism core’s Button uses), so it always looks like a button. The contrast guarantee applies the moment you pick a palette background; the theme-default state’s contrast is the theme’s responsibility, exactly as with core buttons. ### My theme defines palette colors as CSS variables — does the contrast check work? Yes. Palettes in the `var(--name, #hex)` format used by many popular themes are fully supported. A color whose value genuinely can’t be resolved (for example `color- mix(...)`) is not offered for buttons rather than being silently unchecked, and the sidebar explains why. ### Why can’t I pick a heading level? That’s the point: hand-picked levels are how outlines break. The level always derives from section nesting, so reordering can never skip a level or create a second H1. If you need a specific level, nest (or un-nest) the section — the outline follows the structure. ### What happens if I deactivate the plugin? Static content (sections, cards, notices’ inner content) remains as clean HTML. Dynamic blocks (headings, buttons, accordions, table of contents) stop rendering their markup but your content is preserved and reappears on reactivation — nothing is lost. ### Does it phone home? No. Zero external HTTP requests, no tracking, no accounts. ## Reviews There are no reviews for this plugin. ## Contributors & Developers “Guardrail Blocks” is open source software. The following people have contributed to this plugin. Contributors * [ BreonWilliams ](https://profiles.wordpress.org/breonwilliams/) [Translate “Guardrail Blocks” into your language.](https://translate.wordpress.org/projects/wp-plugins/guardrail-blocks) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/guardrail-blocks/), check out the [SVN repository](https://plugins.svn.wordpress.org/guardrail-blocks/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/guardrail-blocks/) by [RSS](https://plugins.trac.wordpress.org/log/guardrail-blocks/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 0.1.2 * Fixed: Accordion content is now reachable without JavaScript, as documented. WordPress’s server-side processing of Interactivity API directives was rendering every panel hidden; panels are now open in the page markup and collapse when the script loads, without a layout shift. Collapsed panels can be found with the browser’s find-in-page where supported, which opens them. * Fixed: Table of Contents links now point to the right heading when several posts render on one page (for example a blog index that shows full posts). * Fixed: Table of Contents now links core Heading blocks whose HTML anchor was saved by an earlier WordPress version. * Fixed: the Accessible Button’s color picker kept only Global Styles custom colors once any were added, hiding the theme palette. Theme and custom colors are now offered together, and when a custom color overrides a theme color, that is the color the contrast check uses. * Improved: Media Figure’s `sizes` attribute now follows the block’s alignment and the theme’s content/wide widths, so wide and full-width images no longer load undersized files. * Editor: the Accordion Item header and Media Figure no longer trigger an accessibility warning or a deprecation notice in the editor. * Tested up to WordPress 7.1. #### 0.1.1 * Heading levels are now also derived from the block tree’s actual nesting on every render, so a stored level can never produce a wrong heading — the outline guarantee is enforced server-side end to end. * New theme-friendly design controls via core block supports: border on Card and Accordion; border radius on Button and Media Figure (rounds the image); padding on Accordion; font size on Accordion, Notice, and Table of Contents; margin on Accessible Heading. * Fixed: the Button’s border radius now previews live in the editor with themes that style `wp-element-button` (Blocksy and similar). #### 0.1.0 * Initial release. * Blocks: Accessible Section, Accessible Heading, Accessible Button, Card + Card Grid, Accessible Accordion, Notice, Media Figure, Table of Contents. * Contrast engine (editor + server) with support for hex, rgb(), and var()-fallback theme palettes. * Heading levels derived from section nesting with self-correction on reorder; Outline Checker panel. * Accordion built on the WordPress Interactivity API with the WAI-ARIA disclosure pattern. * Five patterns including the Starter Brochure Page. ## Meta * Version **0.1.2** * Last updated **2 days ago** * Active installations **Fewer than 10** * WordPress version ** 6.9 or higher ** * Tested up to **7.1.2** * PHP version ** 8.0 or higher ** * Language * [English (US)](https://wordpress.org/plugins/guardrail-blocks/) * Tags * [accessibility](https://li.wordpress.org/plugins/tags/accessibility/)[blocks](https://li.wordpress.org/plugins/tags/blocks/) [contrast](https://li.wordpress.org/plugins/tags/contrast/)[headings](https://li.wordpress.org/plugins/tags/headings/) [wcag](https://li.wordpress.org/plugins/tags/wcag/) * [Advanced View](https://li.wordpress.org/plugins/guardrail-blocks/advanced/) ## Ratings No reviews have been submitted yet. [Your review](https://wordpress.org/support/plugin/guardrail-blocks/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/guardrail-blocks/reviews/) ## Contributors * [ BreonWilliams ](https://profiles.wordpress.org/breonwilliams/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/guardrail-blocks/)