Block, FSE, hybrid, universal? What are these new WordPress themes called? – WP Tavern

Ellen Bauer, developer and co-owner of ElmaStudio, posed the question many have been asking on Twitter last week. What are these new types of WordPress themes made from blocks called? She wasn’t the first to ask. The question was also asked via the Post Status Slack chat earlier this week.

The short answer is that these new themes are “block themes“.

The WordPress themes team decided to use this terminology in December 2021. The consensus at their meeting was to clarify the difference between block themes and classic themes.

The terminology also grew organically as the new theme system emerged. Block themes are themes that are literally made from blocks. The long-term goal should be to just call them “themes,” but the “block” prefix will stick with us for a while.

The long answer is more nuanced. As Anne McCarthy noted in the publication status discussion, there are now four types of themes:

  • To block
  • Classic
  • Hybrid
  • Universal

Technically, developers can create a completely custom theme system. That’s how flexible WordPress is, but we’ll stick to the slightly more official definitions. There are enough terms for our own little mini dictionary of themes as it is.

Block Themes

Editing a block theme via the site editor.

Block themes have been officially supported since the release of WordPress 5.9 last month. They allow users to access new tools such as the site editor and global style interfaces. These features replaced many earlier settings pages, such as the customization and widget screens.

Twenty Twenty-Two is the first default tool to support this new toolset. There are also a small but growing number of other block themes.

Why don’t we call them ESF themes? The full site edition is a set of components and not just one thing. WordPress released several of these components before version 5.9, such as template editor, block-based widgets and theme.json Support. In a sense, a classic theme with any level of feature support is also an FSE theme.

What differentiates block themes from regular themes is that they are built from HTML templates that consist entirely of blocks. This automatically activates the site editor, template editor, global styles interface, etc.

Classic and hybrid themes

The WordPress customizer is open.  On the left is a set of control panels.  On the right is a frame with the site's home page in view.
Customization of Twenty Twenty, a classic theme.

I have grouped classic and hybrid themes together because there is no need to differentiate between the two.

Classic WordPress themes are the ones we’ve known and loved all these years. They feature PHP-based templates in most cases. Some, like Foxhound, are mostly made up of JavaScript. However, none have the necessary block HTML templates to qualify as a block theme.

Hybrid themes are classic themes that have adopted one or more FSE components, such as the template editor or theme.json.

I don’t separate the two types of themes because we’ve never done this before when themes adopt new features. For example, when the navigation menu system was first introduced, there was no need to name themes differently depending on whether or not they supported the new menu system. The same can be said for most other features in the past.

If anything, the official theme directory may need to expand its tags to include additional functionality as it arises. Filters allow users to search for what they want from a theme.

Universal themes

Universal themes work in both a classic and site-builder context. Ben Dwyer offered a more in-depth explanation via the Theme Shaper blog last year:

Universal themes are an attempt to bridge the gap between classic themes and block themes, adding layers to a block theme to make it work.

A Universal theme is a block theme that can use the Full Site Editor but can also be configured in a more classic way. This means that you can use the classic WordPress tools, like the Customizer, Menus and Widgets dashboards as well as the Site Editor.

I haven’t seen much appetite from developers to create universal themes. I don’t know if there are any, at least not in the official directory.

It’s too early to tell if they’ll eventually catch up with the theme writers. Support for classic and modern WordPress tools probably only makes sense for the most popular themes. Their authors may need to rework their codebase, opt for more FSE features, and move from a classic/hybrid state to universal support. If the demand is there, some will no doubt respond.

The support and maintenance charge would be unappealing to most. A clean break from the classic is probably the best route for developers building with the latest WordPress features.


Naming things is difficult, but it is crucial to have an equal footing among the participants in the discussions. The distinction between classic themes and blocks will probably be the most useful.

I doubt the terms matter much to the average WordPress user. They need to know if a theme supports feature X or feature Y. It’s been a while since theme tags (filters) have been revised, and many are outdated. They might be worth revisiting to make sure we’re meeting the needs of users today.

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