Drupal is an open-source content management system (CMS) that powers simple and complex websites and is therefore used by by countless small-businesses as well as being the powerhouse behind many institutional and government websites, ie whitehouse.gov. Its greatness is in how content can be composed of flexible parts.

Site Builds
Set up and maintenance of a Drupal website application. Perfect for e-commerce, libraries, warehouse management and plain-old websites

Data Modeling
Building the content structure and their various display modes

Module Development
Backend programming of logic specific to your needs

Theme building
The display side of Drupal is called a theme and can be designed to your exact specification

Components
Composable blocks that can be placed into a page

Configuration Management
Update the administrative settings are saved to the database and can also be locked down in code

Debugging
Fixing Drupal and PHP notices, warnings and errors that occur during page-load using log files, New Relic, web-profiler and other tools

Code Refactor
Rewriting logic to adapt to changes or simply for the performance gains from tighter efficiency 

PHP
The language the powers Drupal and much of the internet. 

JavaScript
A  dynamic, front-end layer that manages and mutates a webpage's code structure (DOM)