Guacamole is an HTML5 web application that provides access to desktop environments using remote desktop protocols such as VNC or RDP. A centralized server acts as a tunnel and proxy, allowing access to multiple desktops through a web browser. No plugins are needed: the client requires nothing more than a web browser supporting HTML5 and AJAX. guacamole-ext is a Java library used by the Guacamole web application to allow its built-in functionality, such as authentication, to be extended or modified. guacamole-ext provides an interface for retrieving a set of authorized connection configurations for a given set of arbitrary credentials. Classes implementing this interface can be referenced in guacamole.properties to allow different authentication mechanisms to be used.