FSE Block Theme Development — EU, US & Australia
FSE Block Theme Development Built Right
Custom WordPress block themes with reusable patterns and our proven four-pass validation system. Production-ready FSE themes for agencies and SMEs. Hourly or fixed-price, no retainers.
Moiraine theme on WP.org
Four-pass validation system
108+ reusable block patterns
Trellis/FSE experts since 2017
What We Build
Modern WordPress Themes with FSE
We create block themes that leverage Full Site Editing for maximum flexibility, performance, and client empowerment. No page builders, no bloat.
Custom Block Themes
FSE themes built from scratch using Moiraine as our foundation. Semantic theme.json, reusable patterns, and minimal custom CSS. Tell us about your project →
Pattern Library Creation
108+ reusable block patterns like those in our Elayne library. Hero sections, cards, testimonials, pricing tables — all validated with our four-pass system. Learn about validation →
Classic to FSE Migration
Migrate your existing classic theme to a modern FSE block theme. We handle template conversion, pattern extraction, and style mapping. Get a migration quote →
FSE Consulting & Training
Need guidance on FSE adoption? We offer consulting for agencies and development teams. Strategy, best practices, and hands-on training. Schedule a consultation →
theme.json Styling
Complete theme.json configuration with color palettes, typography scales, spacing presets, and layout definitions. Semantic variables throughout. Request styling help →
Agency White-Label
We work behind the scenes for agencies. Your client gets a production-ready FSE theme; you get credit. Discreet, professional, reliable. Ask about white-label →
Why Choose Imagewize for FSE Development
Roots Ecosystem Experts
We’ve been using Trellis, Bedrock, and Sage since 2017. Moiraine is our production-ready FSE block theme, submitted to WordPress.org. We know modern WordPress development inside out.
Four-Pass Validation
Our proprietary four-pass validation system catches structural, semantic, runtime, and template issues before they reach production. Fewer bugs, faster deployment, happier clients.
Transparent Pricing
Hourly rates from €80-120/hour or fixed-price project quotes. You know the cost before we start. No retainers, no lock-in, no minimum commitment. Pay as you go.
15+ Years WordPress Experience
Building WordPress sites since 2009 for clients across Europe, the US, and Australia. We’ve seen it all — and we know how to build it right with FSE.
FSE Block Theme Development Pricing
Custom quotes based on scope. Hourly or fixed-price options available. No retainers, no lock-in.
Custom Block Pattern
Single reusable block pattern for your theme
from €150 fixed price
✓ One custom block pattern
✓ Four-pass validation included
✓ Semantic variables & translations
✓ Ready for production deployment
Pattern Library MOST POPULAR
10-20 custom block patterns for your theme
from €750 fixed price
✓ 10-20 custom block patterns
✓ Organized pattern categories
✓ Four-pass validation on all patterns
✓ Documentation & usage examples
✓ Theme.json integration
Custom FSE Theme
Complete block theme based on Moiraine
from €2,500 fixed price
✓ Moiraine-based FSE theme
✓ 20-30 custom block patterns
✓ Complete theme.json configuration
✓ Template parts (header, footer, etc.)
✓ Staging deployment & testing
Frequently Asked Questions
What is Full Site Editing (FSE) in WordPress?
Full Site Editing is WordPress’s modern approach to theme development that allows you to visually edit every part of your site — headers, footers, templates, and archives — using blocks. Unlike classic themes that rely on PHP template files, FSE themes use HTML templates and theme.json for styling, making them more flexible and client-friendly.
How is an FSE theme different from a classic WordPress theme?
Classic themes use PHP template files (header.php, single.php, etc.) and require code changes for layout modifications. FSE themes use HTML templates and block patterns, allowing visual editing of the entire site through the block editor. FSE themes are typically lighter (no page builder overhead) and give clients more control over their site’s appearance.
What is your four-pass validation system?
Our four-pass validation system ensures production-ready block patterns. Pass 1 validates Gutenberg structural integrity (JSON syntax, block nesting), Pass 2 checks Elayne/Moiraine compliance (semantic variables, translations), Pass 3 tests runtime behavior in a real browser (JavaScript serialization), and Pass 4 validates HTML templates. This catches issues at every layer before deployment. Learn more about our validation system.
How long does FSE theme development take?
A single custom pattern typically takes 1-2 days. A pattern library with 10-20 patterns takes 1-2 weeks. A complete FSE theme development project usually takes 3-6 weeks depending on complexity, pattern count, and custom block requirements. We’ll provide a detailed timeline with your quote.
Can you migrate my existing theme to FSE?
Yes. We can migrate your classic WordPress theme to a modern FSE block theme. This involves extracting your existing styles into theme.json, converting PHP templates to HTML templates, and creating reusable block patterns from your current layout components. Migration pricing starts at €1,500 depending on theme complexity.
Do you offer white-label services for agencies?
Absolutely. We regularly work with agencies as a white-label technical partner for FSE theme development. Your client gets a production-ready block theme; you take the credit. We handle all development, validation, and testing — you manage the client relationship. Available for both hourly and fixed-price engagements.
What’s included in theme.json configuration?
theme.json is the central configuration file for FSE themes. We configure color palettes (with semantic variable names like `var:preset|color|primary`), typography scales with font families and sizes, spacing presets, layout definitions (content width, wide width), and block-specific styles. This allows consistent styling across all patterns and templates with minimal custom CSS.
Do you work with any hosting provider?
Yes. We develop FSE themes for sites on any hosting platform — WP Engine, Kinsta, SiteGround, Cloudways, DigitalOcean, Vultr, Hetzner, or our own Trellis-based VPS. We can also recommend the best hosting setup for your FSE theme based on your traffic, budget, and performance requirements.
Ready to Build with FSE Block Themes?
Tell us about your project and we’ll send a custom quote within one business day. Fixed-price or hourly options available. No commitment required.