Huggle is a fast diff browser application intended for dealing with vandalism or other unconstructive edits on Wikimedia projects, written in C++ using the Qt framework. It was originally developed in .NET Framework by Gurch, who is no longer active on this project. Anyone can download Huggle, but rollback permission is required to use it without restrictions on the English Wikipedia.
Huggle is able to load and review edits made to Wikipedia in real time, helps users identify unconstructive edits, and allows them to be reverted quickly. Various mechanisms are used to draw conclusions to whether an edit is constructive or not. It uses a semi-distributed model where edits are retrieved using a "provider" (this can be anything that is capable of distributing a stream of edit information, such as the Wikipedia API or IRC recent changes feed), pre-parsed and analyzed. This information is then shared with other anti-vandalism tools, such as ClueBot NG. Huggle also uses a number of self-learning mechanisms, including a global white-list (users that are considered trusted) and user-badness scores that are stored locally on the client's computer.
Huggle is connected to MediaWiki through a network API and retrieves a list of edits that are made to a wiki in real time. Huggle evaluates these edits and moves them to a queue from which user can open them. If an edit contains problems, the user can easily revert it, usually with a shortcut key such as Q (by default this reverts the edit and warns the user who made it).