aNag is a free, unofficial client for Icinga, Thruk, Naemon, and Nagios that provides sysadmins with an embedded overview of all their monitored infrastructure. The application is designed to work with multiple instances of Icinga (1.x or 2 with classic-ui), Thruk (at least 2.32), Naemon (w/ Thruk), Nagios, OpsView, and EyesOfNetwork. It also offers client certificate authentication, self-signed certificate exception on a per-instance basis, and no server side modification requirements, only stock CGI.

aNag features background auto-refresh, service filtering, customizable notifications, pattern-based filtering, quiet hours, critical-only mode, and multiple actions available directly in the app. The app can acknowledge, enable/disable notification, submit passive check, recheck, and manage downtime (set and remove). The widgets come in multiple sizes, and the app can warn you even in silent or vibrate mode. Furthermore, the app offers native gzip support and Quick auth for basic authentication.

The app also offers a comprehensive list of preferences with summaries and comments, and a complete changelog is available on the developer's website. If you have any questions or feedback, the developer can be reached via email or on social media.