INVITE is a compact (1.5 Mbyte) programme written entirely in Java. It needs only for a Java Run time Environment (JRE) of version 1.4 or higher to be available. This means it can be launched from the ISDA and run on the client machine as a Java application. Subsequent operations on even relatively large data-sets are rather rapid, since it then runs entirely on the client side. INVITE can also be used in a stand-alone mode to manipulate data from one or more OGIP compliant FITS light-curves.

INVITE allows the user to: simultaneously display a number of light-curves, combine light-curves from different energy bands, generate hardness ratios and re-bin light-curves in time. If a number of light-curves covering adjacent bands are available, these can be used to generate a broadband spectrum which can be passed to XSPEC. Furthermore, an image meta data query can be executed using the Virtual Observatory (VO). If images are available, they can be displayed and manipulated with DS9.