Block support: Align

This document is part of the WordPress block reference and is intended for developers.

Block supports are a set of options that enables or disables block controls in the editor. Block supports are added to the block’s block.json file during block development (Not to be confused with theme.json which is used in theme development).

Documentation

Last updated January 27, 2023.

The align block supports include none (which is the default content width set by the theme, centered in the editor), left, right, center, wide, and full width.
Align is opt-in, and you can enable the alignments individually.

At this time, there is no known way to remove align none, even by filtering the block supports.

To enable all alignments in your custom block, set the value of supports > align to true:

"supports": {
    "align": true
}

To only enable some of the alignments, you can use an array of strings with the alignment name:

"supports": {
	"align": [ "wide", "full" ]
}

Lastly, the alignment block supports also include alignWide, which I believe is a “left over” from before the block supports were moved from the index file to block.json.
alignWide is used to enable or disable wide align. It defaults to true. It is currently only used inside the site logo, avatar, and button. These blocks first enable all alignments, and then removes wide, instead of using the array described above:

"supports": {
	"align": false,
	"alignWide": false
}
List all WordPress core blocks with complete align support:

Many text based blocks only support wide and full because they have a separate text align setting that positions the text to the left, right and center.

List all WordPress core blocks that registers support specifically for align full:
List all WordPress core blocks that registers support specifically for align wide:

View blocks per attribute or block support: