# WordPress How to register block variations with PHP

https://www.hostcarts.qa/knowledgebase/article/wordpress-how-to-register-block-variations-with-php

## Block variations hook and callback

Technically, WordPress 6.5 doesn’t create a standard set of API functions to use for registering variations. But it does add a new filter hook named `get_block_type_variations`, which lets you inject custom variations from either a plugin or theme.

Take a look at the `get_block_type_variations` filter hook:

```php
apply_filters(
	'get_block_type_variations',
	array $variations,
	WP_Block_Type $block_type
);
```

As shown, the hook can pass up to two parameters to any filters that are applied to it:

- **`$variations`:** An array of registered variations for the specific block.
- **`$block_type`:** An instance of the [`WP_Block_Type`](https://developer.wordpress.org/reference/classes/wp_block_type/) class, representing a registered block type.

When defining a filter for the hook, you will almost always need both of these parameters. So be sure to set the `$accepted_args` parameter to `2` when calling the [`add_filter()`](https://developer.wordpress.org/reference/functions/add_filter/) function.

The following is an example of a fictional filter on `get_block_type_variations` to familiarize you with how it should be formatted:

```php
add_filter( 'get_block_type_variations', 'themeslug_block_type_variations', 10, 2 );

function themeslug_block_type_variations( $variations, $block_type ) {

	if ( 'namespace/block-a' === $block_type->name ) {
		// Add variations to the `$variations` array.
	} elseif ( 'namespace/block-b' === $block_type->name ) {
		// Add more variations to the `$variations` array.
	}

	return $variations;
}
```

It’s always necessary to run an `if` conditional check to determine whether the block is the one you want to define a variation for. You can use the `name` property of the `$block` parameter to do this.

Your filter function can also add multiple variations for a single block or define variations for multiple blocks by appending them to the `$variations` parameter.

## Building a custom variation

Now it’s time to get to the fun part: registering a custom block variation!

For this example, let’s use PHP to recreate a JavaScript-based example from the [Variations API](https://developer.wordpress.org/block-editor/reference-guides/block-api/block-variations/) Block Editor Handbook documentation. The variation makes a single attribute change: it moves the media section from the Media & Text block to the right.

When inserted into the Block Editor, the variation will look like this:

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