Tools, broadly speaking, are software applications that interact with the Wikimedia projects but are not fully integrated with them. Tools can be thought of as "external" to the wikis, meaning officially deployed MediaWiki extensions would not be considered tools. However, on-wiki JavaScript gadgets can be thought of as tools, since they consist of user-written code not subject to the usual controls. Tools also include web applications and bots.

Tools can be used for many purposes, including identifying quick editing tasks, semi-automatically performing a large number of very similar edits, visualizing data, extracting metadata, and editing and using wiki content in general.

Different services have made computing resources and web hosting available free of charge to tool developers, starting with Wikimedia Deutschland's Toolserver from 2005 to 2014 and the Wikimedia Foundation's Toolforge (formerly Tool Labs) since 2013. The Toolhub project is trying to create a comprehensive directory of community-developed tools.