The simplest integration method can be used where the Joomla extension already triggers events that can be picked up by a plugin. To use this requires the creation of a UserPoints plugin. These are usually quite simple and can be provided on request for generally useful Joomla extensions.

Payment handling is often done by the use of plugins of some kind. Unfortunately, different developers use different schemes. Some developers even use different schemes within their own extensions. There are a few UserPoints payments plugins that enable purchases with points. Writing new ones is quite complex. As the revenue from UserPoints is very small, it is hard to avoid charging for this. A ball park cost for a new payment plugin is $500.

A relatively simple integration can be achieved it the developer of the Joomla extension is willing to create one or more new plugin triggers that can be used by a UserPoints plugin.

It is quite easy for an extension to call UserPoints. Basic operations such as awarding points can be done in a few lines of code. The mechanisms are described in the API guide. I am always willing to answer questions on how to use the API. Changes to an extension really need to be done by its developer, otherwise they will be a constant problem for upgrades.