Key Takeaways: Block themes are Full Site Editing. Saying “we're waiting for FSE to mature” while pitching a block theme rebuild is the same as saying “we're waiting for cars to mature” while test driving a Tesla. The capability shipped in WordPress 5.9, hardened in 6.2, and is now boring infrastructure. The only thing still maturing is the agency's sales pitch.
You opened a discovery call, screenshared the client's broken site, and the moment you said “block theme rebuild,” the prospect tilted their head. “Isn't that the Full Site Editing thing that's not ready yet?” Somewhere, a YouTuber from 2022 is still nodding. Meanwhile, you're paying for Elementor Pro on twelve client sites and quietly dying inside.
Here is the clean truth: the block theme is the FSE. There is no “FSE thing” that block themes are waiting on. They are the same surface area. If you can install Twenty Twenty-Four, you can ship FSE today. The naming confusion is the last excuse standing between your agency and a 40% margin lift on rebuild projects. Let's bury it.
What Full Site Editing Actually Is (No Marketing Fluff)
Full Site Editing is not a plugin, not a roadmap item, and not a future feature. According to the official WordPress developer documentation, FSE is the umbrella term for three native capabilities stacked into block themes:
- Site Editor for editing templates, template parts, and navigation
- Global Styles powered by
theme.jsonfor typography, color, and spacing - Block-based templates stored as HTML in the database instead of PHP files
Block themes are the only theme type that enables all three. A classic theme can ship with one or two of these features, but only block themes ship the full FSE experience out of the box. So when a client asks “is FSE ready,” the honest answer is: “FSE is the same thing as the block theme I am about to install. We can ship Monday.”
Why Agencies Still Pitch the Fear (and How to Flip It)
Most freelancers I talk to still lead with risk language. “FSE is young,” “the ecosystem is catching up,” “we should wait another year.” That framing loses deals. The client hears “you will be my guinea pig.”
Flip the script. Lead with the boring-mature angle:
- Block themes have shipped in core since WordPress 5.9 (January 2022)
- WordPress 6.2 (May 2023) made Site Editor the default landing screen for block themes
- WordPress 6.6 added synced patterns, partial syncing, and block bindings
- WordPress 6.8 hardened pattern overrides and refined the CSS load order
That is not “young.” That is six years of iterative hardening. The agencies still calling FSE experimental in 2026 are the same ones who called React “just a Facebook toy” in 2016.
The Block Theme IS the FSE: A Mental Model Your Clients Will Get
Use this exact analogy on the next call. It works every time.
Think of a classic theme like Microsoft Word. You get a document, you write in it, and the formatting lives in the document itself. Think of a block theme like Google Docs. The document is the page, but the template, header, and footer are separate, editable, and synced across the site. That separation is what FSE actually unlocks. Once a client sees that “editing the header in one place updates it everywhere” is now native, the page builder renewal pitch dies on the spot.
The Hidden Cost of Staying (Yes, This Is a Pitch Section)
Every quarter a client stays on Elementor, three costs compound. First, the license fee. Second, the bloat. Third, the talent ceiling. You can run the full audit I broke down in The Page Builder Bill You Stopped Reading Two Years Ago, and most agencies find 200-500KB of unused CSS shipping to every page load. Block themes deliver the same layouts with zero plugin overhead because the styles live in theme.json and compile to whatever the page actually uses.
That is not a hypothetical win. It is a Core Web Vitals win you can show in a Lighthouse report on the second call. Money talks. Speed talks louder.
Pricing the Migration Without Undercutting Yourself
Stop billing block theme rebuilds like custom PHP work. You are not writing a theme from scratch. You are selecting a parent block theme, configuring theme.json, building a small set of patterns, and migrating content. Price it as a 2-3 week sprint, not a 3-month engagement. That is a faster close, a healthier margin, and a tighter scope the client can approve on the call.
When FSE Is Actually the Wrong Call (Honest Edition)
Discipline matters. FSE is not the answer for every site, and saying so would make me a hype man, not a strategist. Skip the block theme pitch if:
- The client needs a complex custom post type UI with deeply nested repeaters (use ACF Pro or Meta Box instead)
- The site depends on a page builder-specific feature with no block equivalent (rare, but it still exists)
- The client refuses to give the marketing team block editor access (in that case, FSE will fail regardless)
Outside those three, block themes win. They are leaner, faster, and future-proof. WordPress core is betting the entire roadmap on blocks, and betting against core is a six-figure mistake every single time.
FAQ: Block Themes vs FSE Questions You Will Get This Week
Is FSE the same as Gutenberg? No. Gutenberg is the block editor (the writing experience). FSE extends blocks into the entire site: templates, parts, navigation, and global styles.
Can a classic theme use FSE features? Partially. A classic theme can support theme.json and global styles, but it cannot use the Site Editor for templates. Block themes are the only theme type with full FSE.
What is the most stable block theme to start with on client work? For 2026, start with Twenty Twenty-Four, Blockify, or Frost. Twenty Twenty-Four is the safest baseline because it is a core default and receives direct WordPress.org maintenance.
Will FSE replace Elementor entirely? For most marketing sites, yes. For sites that need heavy custom widgets or visual design tools, a hybrid approach (block theme + lightweight plugin like GenerateBlocks) covers 95% of use cases without the bloat.
Ship the Pitch: Your Next 7 Days
Pull the last three Elementor renewal emails from your inbox. Open three client sites. Run a Lighthouse audit on each. Save the PDFs. Build a one-page deck that says: “Here is the cost you are paying, here is the speed you are losing, here is what a block theme rebuild looks like.” Lead the next call with that deck and the mental model above. You will close at least one rebuild this month, and that one rebuild pays for the rest of the year.
The “FSE is not ready” myth is a sales objection, not a technical one. Kill it on the call, ship the rebuild, and stop funding page builder roadmaps with your client's renewal money.
