Many existing software platforms like Magento, Facebook, Wordpress etc. provides a way for developers to add additional custom functionality to the platform, i.e. a Google map with GPS, Disqus comments etc.

In general, extension/plugin development is fairly simple and can be done by a programmer who has knowledge of the specific platform's API (Application Programming Interface) - in Layman's, an API is software that enables the extension or plugin to communicate with the platform i.e. Facebook.

There are millions of free extensions/plugins available on the Internet. These extension can normally be downloaded and installed via the platform i.e. Joomla, which requires no programming knowledge.

If you have browsed the Internet and could not find a suitable plugin or maybe you found one but its not 100% what you had in mind, then I can help you to either build the plugin from scratch or alter the existing plugin to your requirement.

Some API integration and plugin services I offer: Some of the websites/platforms I developed required me to also develop a custom API for the communication from satellite/remote user sites.