Techniques are disclosed relating to contextual authentication across different applications based on user communications. In some embodiments, a user is preauthenticated to certain actions on a second application based on the user's communication via a first application. The user's communication via a first application provides contextual information that may be used to preauthenticate a request to perform an action on the second application. Contextual information may include the user's communication itself, communications characteristics that are determined from the user's communications, or both. In some embodiments, the degree of preauthentication progressively increases or decreases with the degree of use on the first application; that is, the user is preauthenticated to greater or fewer portions of an authentication procedure, to perform greater or fewer actions, or to perform actions more or less critical to security, as additional information regarding the user's communication on the first application becomes available. In some embodiments, preauthentication may be revoked as additional contextual information becomes available on the first application.