Layout Builder

Philosophy: Configuration-first approach. Layout Builder configuration lives in core.entity_view_display.*.yml with sections and components. Understand config schema, prioritize defaults over overrides, and use config management for deployment.

I Need To...

I need to...	Guide	Summary
Understand what Layout Builder does and when to use it	Overview	When you need visual layout control for entity displays — sections, multiple columns, block-based composition, per-entity or per-bundle layouts.
Enable LB on a content type or entity view mode	Enabling Layout Builder	When you want to enable Layout Builder on a content type, custom entity type, or specific view mode.
Read and edit LB configuration YAML	Config Schema	When reading, editing, or generating Layout Builder configuration in YAML files, understanding config structure for recipes, programmatic manipulation, or debugging.
Understand section structure and layout plugins	Sections & Layouts	When you need to understand how sections work, what layout plugins provide, and how regions structure content within a section.
Find available core layout plugins	Core Layout Plugins	When selecting a layout for a section or creating custom layouts based on core patterns.
Add blocks to layouts programmatically	Block Placement	When adding blocks to Layout Builder sections programmatically, understanding component structure, or manipulating block configuration.
Decide between inline and reusable blocks	Inline vs Reusable	When deciding between non-reusable inline blocks (created within Layout Builder) and reusable block content entities.
Expose entity fields as blocks in layouts	Field & Extra Field Blocks	When exposing entity field data or extra fields (pseudo-fields) as blocks in Layout Builder layouts.
Choose between default layouts and per-entity overrides	Defaults vs Overrides	When deciding whether to allow per-entity layout customization or use a single default layout for all entities of a bundle.
Restrict which blocks editors can add	Layout Builder Restrictions	When you need to limit which blocks, layouts, or sections editors can add in Layout Builder to prevent overwhelming choices or enforce content governance.
Apply CSS classes to sections and blocks	Layout Builder Styles Overview	When you need to apply CSS classes to Layout Builder sections (layouts) or components (blocks) without creating custom plugins. Layout Builder Styles provides a config entity system for defining reusable style options that editors select…
Create style groups and styles via YAML config	Style Groups Config	Style groups organize related styles into categories (e.g., "Padding", "Background Color", "Border Style"). Editors see one form element per group, making the UI manageable when you have many styles.
Define individual styles with restrictions	Style Definitions	Individual styles define CSS classes to apply, which blocks/sections can use them, and which group they belong to. Styles are config entities exported as YAML for deployment via config sync.
Integrate LB Styles with Bootstrap/Radix	Bootstrap Integration	When using Bootstrap-based themes (Radix, Bootstrap Barrio), map Layout Builder Styles to Bootstrap utility classes for consistent design system integration. Avoids custom CSS for common patterns.
Extend LB Styles programmatically	Extending LB Styles	When you need to programmatically alter which styles are available, modify CSS classes before rendering, or integrate custom logic into the style selection process.
Use UI Patterns as LB layouts + UI Styles	UI Patterns Layouts & UI Styles Integration	When you want SDC components to serve as Layout Builder section layouts without writing custom *.layouts.yml or LayoutDefault plugins. Also covers UI Styles module as an alternative to Layout Builder Styles for CSS class management.
Create custom layout plugins	Custom Layout Plugins	When core layouts don't provide the regions or structure you need, or when you want theme-specific layouts.
React to layout rendering with events	Events & Hooks	When you need to alter layout rendering, modify section/component behavior, or integrate custom logic during layout building.
Export and deploy LB configuration	Config Export & Recipes	When deploying Layout Builder configuration across environments, creating reusable layout patterns, or managing LB config in version control.
Style LB admin UI and frontend output	Theming Layout Builder	When styling Layout Builder admin UI, layout frontend output, or section/component markup.
Follow configuration-first best practices	Best Practices	When establishing Layout Builder workflows, governance, or making architectural decisions.
Avoid common mistakes	Anti-Patterns	When you need to know what NOT to do — these are patterns that seem logical but cause problems.
Understand security and performance implications	Security & Performance	When hardening Layout Builder against security issues, optimizing performance, or auditing for vulnerabilities.
Find key classes and files	Code Reference Map
Check sources and version history	Sources & Maintenance