The free version of s2Member®, is referred to as the s2Member® Framework. It supports PayPal® Standard Button integration through WordPress® Shortcodes. Suitable for most sites.

This documentation also covers routines introduced by s2Member® Pro (an optional paid upgrade). s2Member® Pro adds support for PayPal® Pro, Authorize.Net®, Google® Checkout, and ClickBank®. In addition, s2Member® Pro includes User Import/Export tools, Coupon Codes, and a Pro Login Widget (plus Profile Summary). Your purchase of s2Member® Pro includes free upgrades via s2Member.com (new features, bug fixes, updates, improvements), along with full access to our video tutorial library.

Hacking s2Member® (it's easy with Hooks/Filters for WordPress®)

If you need to add custom processing routines, or modify the behavior of existing processing routines; please use s2Member's Hooks/Filters for WordPress®. Hooks & Filters, give you the ability to "hook into", and/or "filter" processing routines, with files/functions of your own; instead of editing the s2Member® plugin files directly. This way you won't need to merge your changes/tweaks each time a new version of s2Member® is released. To create custom processing routines, place those routines into a PHP file here: /wp-content/mu-plugins/s2-hacks.php. If you don't have an /mu-plugins/ directory, please create one. These are (mu) MUST USE plugins, which are loaded into WordPress® automatically; that's what you want! If you're not familiar with Hooks/Filters for WordPress®, please read this article in the WordPress® Codex.

Adding a Hook (inside /wp-content/mu-plugins/s2-hacks.php)

Please make sure there are NO blank lines in your PHP file. Do NOT introduce spaces/tabs/lines before or after the <?php ?> tags.

<?php
add_action("hook_name", "my_action_hook_function");
function my_action_hook_function($vars = array())
	{
		echo "My Hook works.";</p><p>		# Optional. s2Member® passes you an array of defined variables.
		# print_r($vars); # Would give you a list of defined variables.
		# These are PHP variables defined within the scope of the Hook,
		# at the precise point in which the Hook is fired by s2Member®.</p><p>		# $vars["__refs"] are also included (with some Hooks).
		# These are internal PHP variable references (very useful).
		# To learn all about references, please see PHP documentation:
		# http://www.php.net/manual/en/language.references.pass.php
	}
?>

Adding a Filter (inside /wp-content/mu-plugins/s2-hacks.php)

Please make sure there are NO blank lines in your PHP file. Do NOT introduce spaces/tabs/lines before or after the <?php ?> tags.

<?php
add_filter("filter_name", "my_filtering_function", 10, 2);
function my_filtering_function($original_value, $vars = array())
	{
		if($original_value !== "something I like")
			return ($my_custom_value = "My Filter works.");</p><p>		else # Return original value.
			return $original_value;</p><p>		# Optional. s2Member® passes you an array of defined variables.
		# print_r($vars); # Would give you a list of defined variables.
		# These are PHP variables defined within the scope of the Filter,
		# at the precise point in which the Filter is fired by s2Member®.</p><p>		# $vars["__refs"] are also included (with some Filters).
		# These are internal PHP variable references (very useful).
		# To learn all about references, please see PHP documentation:
		# http://www.php.net/manual/en/language.references.pass.php
	}
?>