A plugin (or extension) is add-on software that extends the functionality of existing applications. Web browser extensions add features to Chrome, Firefox, or Edge. WordPress plugins extend website capabilities. Software platforms often support plugins from third-party developers, creating ecosystems of specialized tools. Municipal IT systems may use plugins for specific integrations, reporting capabilities, or workflow improvements. While plugins provide flexibility, they can also create security vulnerabilities if poorly maintained or from untrusted sources. IT departments evaluate plugins for security, compatibility, and ongoing support before installation. Plugin management is part of overall software maintenance responsibilities.