add_rewrite_rule() WP 1.0

Adds a rewrite rule that transforms a URL structure to a set of query vars.

Any value in the $after parameter that isn't 'bottom' will result in the rule being placed at the top of the rewrite rules.

No Hooks.

Return

Nothing (null).

Usage

add_rewrite_rule( $regex, $query, $after );

$regex(string) (required)

Regular expression to match request against.

$query(string/array) (required)

The corresponding query vars for this rewrite rule.

$after(string)

Priority of the new rule. Accepts 'top' or 'bottom'.
Default: 'bottom'

Code of add rewrite rule: wp-includes/rewrite.php ^{WP 5.2.1}

<?php
function add_rewrite_rule( $regex, $query, $after = 'bottom' ) {
	global $wp_rewrite;

	$wp_rewrite->add_rule( $regex, $query, $after );
}

Related Functions

From tag: Rewrite (clean friendly URL)