Block Registration Edit

registerBlockType registerBlockType

  • Type: Function

Every block starts by registering a new block type definition. To register, you use the registerBlockType function from the wp-blocks package. The function takes two arguments, a block name and a block configuration object.

Block Name Block Name

  • Type: String

The name for a block is a unique string that identifies a block. Names have to be structured as namespace/block-name, where namespace is the name of your plugin or theme.

// Registering my block with a unique name
registerBlockType( 'my-plugin/book', {} );

Note: A block name can only contain lowercase alphanumeric characters and dashes, and must begin with a letter.

Note: This name is used on the comment delimiters as <!-- wp:my-plugin/book -->. Those blocks provided by core don’t include a namespace when serialized.

Top ↑

Block Configuration Block Configuration

  • Type: Object [ { key: value } ]

A block requires a few properties to be specified before it can be registered successfully. These are defined through a configuration object, which includes the following:

title title

  • Type: String

This is the display title for your block, which can be translated with our translation functions. The block inserter will show this name.

// Our data object
title: __( 'Book' );

Top ↑

description (optional) description (optional)

  • Type: String

This is a short description for your block, which can be translated with our translation functions. This will be shown in the Block Tab in the Settings Sidebar.

description: __( 'Block showing a Book card.' );

Top ↑

category category

  • Type: String [ common | formatting | layout | widgets | embed ]

Blocks are grouped into categories to help users browse and discover them.

The core provided categories are:

  • common
  • formatting
  • layout
  • widgets
  • embed
// Assigning to the 'widgets' category
category: 'widgets',

Plugins and Themes can also register custom block categories.

Top ↑

icon (optional) icon (optional)

  • Type: String | Object

An icon property should be specified to make it easier to identify a block. These can be any of WordPress’ Dashicons, or a custom svg element.

// Specifying a dashicon for the block
icon: 'book-alt',

// Specifying a custom svg for the block
icon: <svg viewBox="0 0 24 24" xmlns=""><path fill="none" d="M0 0h24v24H0V0z" /><path d="M19 13H5v-2h14v2z" /></svg>,

Note: Custom SVG icons are automatically wrapped in the wp.primitives.SVG component to add accessibility attributes (aria-hidden, role, and focusable).

An object can also be passed as icon, in this case, icon, as specified above, should be included in the src property.

Besides src the object can contain background and foreground colors, this colors will appear with the icon when they are applicable e.g.: in the inserter.

icon: {
    // Specifying a background color to appear with the icon e.g.: in the inserter.
    background: '#7e70af',
    // Specifying a color for the icon (optional: if not set, a readable color will be automatically defined)
    foreground: '#fff',
    // Specifying an icon for the block
    src: <svg viewBox="0 0 24 24" xmlns=""><path fill="none" d="M0 0h24v24H0V0z" /><path d="M19 13H5v-2h14v2z" /></svg>,
} ,

Top ↑

keywords (optional) keywords (optional)

  • Type: Array

Sometimes a block could have aliases that help users discover it while searching. For example, an image block could also want to be discovered by photo. You can do so by providing an array of terms (which can be translated).

// Make it easier to discover a block with keyword aliases.
// These can be localised so your keywords work across locales.
keywords: [ __( 'image' ), __( 'photo' ), __( 'pics' ) ],

Top ↑

styles (optional) styles (optional)

  • Type: Array

Block styles can be used to provide alternative styles to block. It works by adding a class name to the block’s wrapper. Using CSS, a theme developer can target the class name for the style variation if it is selected.

// Register block styles.
styles: [
    // Mark style as default.
        name: 'default',
        label: __( 'Rounded' ),
        isDefault: true
        name: 'outline',
        label: __( 'Outline' )
        name: 'squared',
        label: __( 'Squared' )

Plugins and Themes can also register custom block style for existing blocks.

Top ↑

attributes (optional) attributes (optional)

  • Type: Object

Attributes provide the structured data needs of a block. They can exist in different forms when they are serialized, but they are declared together under a common interface.

// Specifying my block attributes
attributes: {
    cover: {
        type: 'string',
        source: 'attribute',
        selector: 'img',
        attribute: 'src',
    author: {
        type: 'string',
        source: 'html',
        selector: '.book-author',
    pages: {
        type: 'number',

Top ↑

example (optional) example (optional)

  • Type: Object

Example provides structured example data for the block. This data is used to construct a preview for the block to be shown in the Inspector Help Panel when the user mouses over the block.

The data provided in the example object should match the attributes defined. For example:

example: {
    attributes: {
        cover: '',
        author: 'William Shakespeare',
        pages: 500

If example is not defined, the preview will not be shown. So even if no-attributes are defined, setting a empty example object example: {} will trigger the preview to show.

It’s also possible to extend the block preview with inner blocks via innerBlocks. For example:

example: {
    attributes: {
        cover: '',
    innerBlocks: {
        name: 'core/paragraph',
        attributes: {
            /* translators: example text. */
            content: __(
                'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent et eros eu felis.'

Top ↑

variations (optional) variations (optional)

  • Type: Object[]

Similarly to how the block’s style variations can be declared, a block type can define block variations that the user can pick from. The difference is that, rather than changing only the visual appearance, this field provides a way to apply initial custom attributes and inner blocks at the time when a block is inserted.

By default, all variations will show up in the Inserter in addition to the regular block type item. However, setting the isDefault flag for any of the variations listed will override the regular block type in the Inserter.

variations: [
        name: 'wordpress',
        isDefault: true,
        title: __( 'WordPress' ),
        description: __( 'Code is poetry!' ),
        icon: WordPressIcon,
        attributes: { service: 'wordpress' },
        name: 'google',
        title: __( 'Google' ),
        icon: GoogleIcon,
        attributes: { service: 'google' },
        name: 'twitter',
        title: __( 'Twitter' ),
        icon: TwitterIcon,
        attributes: { service: 'twitter' },

An object describing a variation defined for the block type can contain the following fields:

  • name (type string) – The unique and machine-readable name.
  • title (type string) – A human-readable variation title.
  • description (optional, type string) – A detailed variation description.
  • icon (optional, type String | Object) – An icon helping to visualize the variation. It can have the same shape as the block type.
  • isDefault (optional, type boolean) – Indicates whether the current variation is the default one. Defaults to false.
  • attributes (optional, type Object) – Values that override block attributes.
  • innerBlocks (optional, type Array[]) – Initial configuration of nested blocks.
  • example (optional, type Object) – Example provides structured data for the block preview. You can set to undefined to disable the preview shown for the block type.
  • scope (optional, type String[]) – the list of scopes where the variation is applicable. When not provided, it assumes all available scopes. Available options: block, inserter.

It’s also possible to override the default block style variation using the className attribute when defining block variations.

variations: [
        name: 'blue',
        title: __( 'Blue Quote' ),
        isDefault: true,
        attributes: { className: 'is-style-blue-quote' },
        icon: 'format-quote',

Top ↑

transforms (optional) transforms (optional)

  • Type: Object

Transforms provide rules for what a block can be transformed from and what it can be transformed to. A block can be transformed from another block, a shortcode, a regular expression, a file or a raw DOM node. Take a look at the Block Transforms API for more info about each available transformation.

Top ↑

parent (optional) parent (optional)

  • Type: Array

Blocks are able to be inserted into blocks that use InnerBlocks as nested content. Sometimes it is useful to restrict a block so that it is only available as a nested block. For example, you might want to allow an ‘Add to Cart’ block to only be available within a ‘Product’ block.

Setting parent lets a block require that it is only available when nested within the specified blocks.

// Only allow this block when it is nested in a Columns block
parent: [ 'core/columns' ],

Top ↑

supports (optional) supports (optional)

Some block supports — for example, anchor or className — apply their attributes by adding additional props on the element returned by save. This will work automatically for default HTML tag elements (div, etc). However, if the return value of your save is a custom component element, you will need to ensure that your custom component handles these props in order for the attributes to be persisted.

  • Type: Object

Optional block extended support features. The following options are supported:

  • align (default false): This property adds block controls which allow to change block’s alignment. Important: It doesn’t work with dynamic blocks yet.
// Add the support for block's alignment (left, center, right, wide, full).
align: true,
// Pick which alignment options to display.
align: [ 'left', 'right', 'full' ],

When supports align is used the block attributes definition is extended to include an align attribute with a string type.
By default, no alignment is assigned to the block.
The block can apply a default alignment by specifying its own align attribute with a default e.g.:

attributes: {
    align: {
        type: 'string',
        default: 'right'
  • alignWide (default true): This property allows to enable wide alignment for your theme. To disable this behavior for a single block, set this flag to false.
// Remove the support for wide alignment.
alignWide: false,
  • defaultStylePicker (default true): When the style picker is shown, a dropdown is displayed so the user can select a default style for this block type. If you prefer not to show the dropdown, set this property to false.
// Remove the Default Style picker.
defaultStylePicker: false,
  • anchor (default false): Anchors let you link directly to a specific block on a page. This property adds a field to define an id for the block and a button to copy the direct link.
// Add the support for an anchor link.
anchor: true,
  • customClassName (default true): This property adds a field to define a custom className for the block’s wrapper.
// Remove the support for the custom className.
customClassName: false,
  • className (default true): By default, the class .wp-block-your-block-name is added to the root element of your saved markup. This helps having a consistent mechanism for styling blocks that themes and plugins can rely on. If for whatever reason a class is not desired on the markup, this functionality can be disabled.
// Remove the support for the generated className.
className: false,
  • html (default true): By default, a block’s markup can be edited individually. To disable this behavior, set html to false.
// Remove support for an HTML mode.
html: false,
  • inserter (default true): By default, all blocks will appear in the inserter. To hide a block so that it can only be inserted programmatically, set inserter to false.
// Hide this block from the inserter.
inserter: false,
  • multiple (default true): A non-multiple block can be inserted into each post, one time only. For example, the built-in ‘More’ block cannot be inserted again if it already exists in the post being edited. A non-multiple block’s icon is automatically dimmed (unclickable) to prevent multiple instances.
// Use the block just once per post
multiple: false,
  • reusable (default true): A block may want to disable the ability of being converted into a reusable block.
    By default all blocks can be converted to a reusable block. If supports reusable is set to false, the option to convert the block into a reusable block will not appear.
// Don't allow the block to be converted into a reusable block.
reusable: false,

Top ↑

Block Collections Block Collections

Top ↑

registerBlockCollection registerBlockCollection

  • Type: Function

Blocks can be added to collections, grouping together all blocks from the same origin

registerBlockCollection takes two parameters, namespace and an object of settings including title and icon.

Top ↑

Namespace Namespace

  • Type: String

This should match the namespace declared in the block name; the name of your plugin or theme.

Top ↑

Settings Settings

Top ↑

Title Title

  • Type: String

This will display in the block inserter section, which will list all blocks in this collection.

Top ↑

Icon Icon

  • Type: Object

(Optional) An icon to display alongside the title in the block inserter.

// Registering a block collection
registerBlockCollection( 'my-plugin', { title: 'My Plugin' } );