How to Master WordPress Full Site Editing (FSE) in 2025

According to WPBeginner 2026 research, over 60% of new WordPress themes released are now block-based FSE themes. This seismic shift represents the future of WordPress development—and if you are still relying on page builders or classic theme customization, you are already behind the curve.

Full Site Editing (FSE) fundamentally changes how WordPress sites are built. Rather than cobbling together page builders, custom CSS, and theme options panels, FSE provides a unified visual interface for controlling every aspect of your site—from headers and footers to post templates and custom taxonomies.

This guide cuts through the noise and shows you exactly how to harness FSE power.

System Requirements for FSE

Before diving into FSE, ensure your WordPress environment meets the minimum requirements. FSE isn't available on every installation—you need the right foundation.

Core Requirements:

• WordPress 5.9 or newer — FSE introduced in WordPress 5.9, but 6.2+ is recommended for stability
• Block-based theme — Not the classic Twenty Twenty-Two or older themes. Must support theme.json
• PHP 7.4+ — Modern PHP versions run FSE features faster
• No page builder plugins — Disable Elementor, Beaver Builder, etc. They interfere with FSE

How to verify you have a block theme: Go to Appearance → Themes. Hover over your active theme. If you see a "Customize" button in Site Editor, it's FSE-ready. Classic themes show the old Customizer instead.

Understanding the Site Editor Interface

The Site Editor (Appearance → Editor) is where FSE magic happens. It's a visual interface that looks like the Block Editor but controls your entire site.

Four Key Sections:

• Templates — Design layouts for posts, pages, archives, search results. Single template controls one post type.
• Template Parts — Reusable components (header, footer, sidebar) that appear on multiple templates.
• Global Styles — Typography, colors, spacing applied sitewide. Centralized design system.
• Patterns — Pre-built block combinations you can insert into templates or posts (like a design library).

Navigate these sections from the left sidebar. Click "Templates" to edit the single post template, "Template Parts" to manage headers/footers, or "Styles" to customize colors globally.

FSE Template Hierarchy & Priority

WordPress FSE follows a strict template hierarchy. When displaying a page, WordPress checks for templates in this order. The first match wins.

Template Hierarchy Priority (highest to lowest):

1. singular-{post-type}-{slug}.html — Specific post by slug
2. singular-{post-type}.html — All posts of a type
3. singular.html — Fallback for all single posts/pages
4. archive-{post-type}.html — Custom post type archives
5. taxonomy-{taxonomy}-{term}.html — Specific category/tag
6. taxonomy-{taxonomy}.html — All categories/tags
7. archive.html — Default archive (posts, categories, etc.)
8. search.html — Search results
9. 404.html — Page not found
10. index.html — Site homepage & ultimate fallback

Understanding this order prevents accidentally creating duplicate templates. If you need different styling for blog posts vs. pages, create singular-post.html and singular-page.html.

Creating Reusable Template Parts

Template Parts are the backbone of FSE efficiency. Instead of duplicating your header code in every template, create it once as a Template Part and reuse it everywhere.

Workflow Example: Creating a Custom Header

1. Go to Site Editor → Template Parts
2. Click "New" → Create "Header"
3. Add your site logo, navigation, tagline, search bar
4. Save the Template Part
5. Now, in any template, click the plus icon → Template Parts → Header
6. Your header appears automatically, linked to the Template Part
7. Edit the Template Part once, and changes appear everywhere it's used

This same process works for footers, sidebars, and any component you want to reuse. Create once, use everywhere, update once—changes propagate sitewide.

Global Styles & theme.json Configuration

Global Styles provide a centralized design system. Instead of tweaking colors and fonts in each block, define them once and apply globally.

Accessible via Styles Panel (WordPress 6.2+): Site Editor → Styles (top-right). Visual interface for colors, typography, spacing without editing code.

Behind the scenes, this manages theme.json: A JSON file defining design tokens. Here's the structure:

{
  "$schema": "https://schemas.wp.org/wp/6.3/theme.json",
  "version": 3,
  "settings": {
    "color": {
      "palette": [
        { "name": "Primary", "slug": "primary", "color": "#0066ff" },
        { "name": "Dark", "slug": "dark", "color": "#1a1a1a" }
      ]
    },
    "typography": {
      "fontFamilies": [
        { "name": "Heading", "slug": "heading", "fontFamily": "Inter, sans-serif" },
        { "name": "Body", "slug": "body", "fontFamily": "Georgia, serif" }
      ]
    }
  },
  "styles": {
    "color": { "background": "#ffffff", "text": "#000000" },
    "typography": { "fontSize": "16px", "lineHeight": 1.6 }
  }
}

Define color palettes, font stacks, spacing scales once. Blocks inherit these tokens. Change primary color in theme.json, and it updates everywhere.

Block Patterns & Pattern Library

Block Patterns are pre-built block combinations—a Hero section, testimonial card, pricing table, contact form, etc. They accelerate template creation.

Pattern Categories:

• Buttons & CTAs — Call-to-action blocks with various styles
• Headers & Heroes — Title + image/video patterns
• Testimonials — Quote blocks with author info
• Pricing Tables — Feature comparison grids
• Contact Forms — Pre-configured form layouts
• Image Galleries — Masonry, grid, carousel styles
• Blog Feed — Post lists with preview cards
• FAQs — Accordion-style Q&A patterns

How to Create a Custom Pattern: Design a block arrangement (e.g., image + text + button). Select all blocks. Right-click → "Create pattern". Name it. Now it appears in your pattern library for reuse.

Advanced developers can register patterns via PHP in theme functions.php using register_block_pattern(). This lets you distribute pre-built templates with your theme.

Advanced FSE Customization

FSE covers 80% of site-building needs. For the remaining 20%, these advanced techniques unlock deeper control.

Custom CSS: Global Styles includes a custom CSS editor. Add CSS rules targeting any block class. This bridges the gap between visual builder and code control.

Block Bindings API: WordPress 6.4+ allows connecting block content to dynamic data (post metadata, site options, custom fields). Example: A block displays the post's custom "featured_highlight" field automatically, updating when you edit post metadata.

Query Loop Block: Display custom post lists with filters. Create "Related Posts" sections, product catalogs, or news feeds. Supports taxonomy, meta queries, and sorting.

Theme.json Inheritance: Organize theme.json across multiple files. Break it into settings.json, styles.json, etc. Imported via $ref property for better maintainability on large projects.

Production Workflow & Migration Strategy

FSE excels for new projects but requires careful handling when migrating legacy sites.

Development Environment: Use a staging WordPress install. Build templates, test patterns, customize Global Styles. Once finalized, export the theme directory (including theme.json) to version control.

Performance Considerations: FSE generates extra database calls for template queries. Enable object caching (Redis/Memcached) and page caching (WP Rocket/Cache Enabler). FSE sites with optimization score 85+.

Accessibility: FSE blocks are WCAG 2.1 compliant by default, but custom patterns must follow semantics. Use heading hierarchy (h1, h2, h3), alt text for images, sufficient color contrast. Test with WAVE or Axe DevTools browser extensions.

Migration from Page Builders: Exporting Elementor/Beaver Builder content to FSE is manual work. Export content as HTML, recreate templates in FSE, map old URLs to new templates. Don't try automated conversion—FSE structure differs fundamentally.

Version Control Best Practice: Commit theme files (including theme.json) to Git. Template Part and Global Style settings live in the WordPress database by default. Use WP-CLI to export/import FSE settings between environments if needed.