Gutenberg is the block-based content editor built into WordPress, introduced in version 5.0 in 2018, which replaced the older TinyMCE-based classic editor with a modular, visual editing experience centered around discrete units of content called blocks.
Named after Johannes Gutenberg, the inventor of the movable type printing press, the editor reflects an ambition to make content creation more flexible and accessible. Rather than working inside a single text field, authors compose pages and posts by combining individual blocks, each representing a specific type of content: a paragraph, an image, a heading, a video embed, a button, or a custom layout column. Each block carries its own settings and can be moved, styled, and configured independently of the others. This approach is conceptually similar to what third-party page builders like Elementor or Divi had offered for years, but Gutenberg integrates this paradigm directly into WordPress core.
The scope of Gutenberg extends well beyond post and page editing. Its second major phase, known as Full Site Editing (FSE), allows users to apply the same block-based interface to every part of a WordPress site, including headers, footers, sidebars, and template layouts. Full Site Editing relies on block themes, a new category of WordPress theme that defines site structure entirely through HTML templates composed of blocks, rather than through PHP template files. This represents a significant shift in how themes are developed and maintained, reducing the need for PHP expertise while giving designers more direct control over layout through the editor itself.
For developers, Gutenberg introduces a JavaScript-heavy architecture built on React. Custom blocks are registered using the Block API and written primarily in JavaScript, which marks a departure from the PHP-centric patterns that dominated WordPress development for most of its history. Developers can also create block patterns, which are predefined arrangements of blocks that users can insert as a starting point, and block variations, which are preset configurations of an existing block type.
The editor also intersects with Custom Post Types, since any post type that supports the editor can take advantage of blocks, patterns, and in some configurations, custom block templates that pre-populate the editing canvas with a specific structure.
From an SEO perspective, Gutenberg produces clean, semantic HTML when used with a well-constructed theme, which supports proper heading hierarchy, structured content, and fast page rendering. The shift to Full Site Editing also means that site-wide structural changes, which previously required theme file edits or child themes, can now be made directly in the browser, making it easier to maintain consistent markup across a site.