Systems and methods are disclosed to authenticate and authorize a user for web services using user devices. In various embodiments, a method may comprise: identifying, by a user device security manager executing at a user device corresponding to a user of a web service, a first request issued from an application to access remote resources associated with the web service, the application executing at the user device and separate from the user device security manager; acquiring, by the user device security manager, security information of the application in response to the identifying of the first request, the security information including at least one of an application identification, an access scope or a nonce of the application; and transmitting a second request from the user device security manager to the web service to authenticate the application by the web service based, at least in part, on the application identification.