Oxygen vs Gutenberg in 2026: Which Should You Build With?

Oxygen was one of the favourite builders of WordPress developers: full design control, clean output, no theme. Since 2025 there are two Oxygens: Oxygen Classic and Oxygen 6, a complete rewrite built on the Breakdance engine. At the same time, the WordPress block editor (Gutenberg) has grown into a real site-building tool with block themes and the Site Editor. If you’re starting a new site, or wondering what to do with an Oxygen site, here’s an honest comparison.

The state of Oxygen in 2026

• Oxygen Classic is still maintained, and existing sites keep working.
• Oxygen 6 (6.1 released in May 2026) is a rewrite that shares most of its core with Breakdance. It’s included for lifetime Oxygen customers. Because it’s a new builder, moving a Classic site to it is a rebuild, not a one-click upgrade.

So “should I stay on Oxygen?” is really two questions: stay on Classic, move to Oxygen 6, or move to the block editor.

Where your content lives

This is the difference that matters most over the lifetime of a site.

• Oxygen stores designs in its own format, in post meta. If Oxygen is deactivated, those pages lose their layout.
• Gutenberg stores content in the post itself, as HTML with block comments. Core blocks keep working with any theme, and even without the plugin that created a custom block, the saved HTML is still in the post.

For sites that should last many years, or be handed to another developer, content that isn’t locked to one builder is a big advantage.

Side by side

	Oxygen (Classic / 6)	Gutenberg (block editor)
Design control	Very high, pixel-level	High with block themes and theme.json, lower in the default UI
Editing for clients	Separate builder UI, easy to break layouts	The normal WordPress editor, locked patterns and blocks keep designs safe
Content lock-in	Tied to Oxygen	Stored as HTML in the post
Performance	Clean output, depends on how you build	Good by default; block themes load only the CSS of blocks on the page
Future	Maintained by one company	Part of WordPress core
Reusable components	Reusable parts, templates	Patterns, synced patterns, custom blocks
Cost	Paid license	Free

Where Gutenberg used to lose

Developers left the block editor for Oxygen for good reasons: little design control, and custom blocks required React and a build step. The first gap has mostly closed with block themes, theme.json, and style variations. The second is still the real hurdle: the official way to build a custom block is a React project.

The missing piece: custom blocks in PHP

Oxygen developers are used to building components with PHP and CSS. That’s exactly how FanCoolo WP builds Gutenberg blocks: you write the block’s output in PHP, style it with SCSS, and add editor fields with a visual attributes manager. The result is a native block that editors insert from the normal block inserter, with native sidebar controls. No React, no npm. Reusable Symbols play the role of Oxygen’s reusable parts. And if you love utility classes, Winden brings Tailwind CSS into the block editor too.

See how to create a custom Gutenberg block without React for a step-by-step example.

So which should you choose?

• Stay on Oxygen Classic for existing sites that work and don’t need big changes. There’s no rush.
• Move to Oxygen 6 if you love the Oxygen way of working and are happy to rebuild in a new builder.
• Choose Gutenberg for new sites that clients will edit, sites that must outlive any one plugin, and teams who want to stay close to WordPress core. With custom blocks built in PHP, you keep most of what made Oxygen productive.