xAct (www.xact.es) is a collection of Wolfram Language packages for Tensor Computer Algebra. After nearly two decades, it has been used in a thousand different projects in mathematical physics, by a growing community that is now adding more packages to the system. In particular, xAct was a key tool in the study of the the Cauchy problem on a characteristic cone for the Einstein equations by Yvonne Choquet-Bruhat, Piotr Chrusciel and the speaker. This talk will describe the current status of xAct, showing examples of use, and discussing future plans.