Tag
The WordPress block editor: blocks, patterns and full site editing.
Troubleshooting
The editor asked the REST API to save the post and got a refusal, a redirect or a non-JSON page back. The second sentence of the message tells you which, and the browser's network panel shows the actual response in under a minute.
WordPress Tutorials
The filter runs before the insert, which is what makes it the right place to force a status or rewrite a title without a second save. It also hands you slashed data, and a string operation that ignores that corrupts every apostrophe.
WordPress Tutorials
A size registered with add_image_size exists for templates and nowhere else. This filter is what puts it in the Image block's Resolution dropdown, and it does nothing for images uploaded before the size was registered.
WordPress Tutorials
The hook registers the box; it does not save anything. Saving is a second hook with a nonce, a capability check and an autosave guard, and a meta box without all three either loses data or accepts it from anyone.
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The column needs two hooks, not one: a filter that registers the header and an action that prints each cell. A column with a header and empty cells has the first and not the second, which is the most common half-finished state.
WordPress Tutorials
The filter hands you the menu as a finished HTML string, which is why it is quick for a login link and useless for anything structural. It also never fires for the Navigation block, which is most menus on block themes.
WordPress Tutorials
Both filters only touch excerpts WordPress generates. A manual excerpt is printed as written, and the Post Excerpt block sets its own length at a priority nothing in functions.php can beat.
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Appending a block of text here is four lines and a recursion bug waiting to happen. The filter runs on archives, in widgets and in the REST response, so content added without a guard ends up in places nobody was shown a preview of.
Troubleshooting
A blank screen, an endless spinner, or a page that will not save almost always traces back to a blocked REST API request or a JavaScript error. Work through causes in order of likelihood rather than guessing.
WordPress Tutorials
Group, Row and Stack are the three container blocks that do most of the layout work in the block editor. Knowing which one to reach for stops layouts from turning into a pile of nested Groups.
WordPress Tutorials
Vertical rhythm in the block editor comes from theme.json, not from each block guessing sensibly. Once you know where the widths and gaps are defined, inconsistent spacing stops being a mystery.
WordPress Tutorials
The site editor, under Appearance, is where a block theme's templates, template parts, styles and patterns all live in one place. It looks like the post editor but edits the frame around your content, not the content itself.