Methods and systems for authenticating users of client devices to allow access of resources and services in enterprise systems are described herein. An authentication device may validate a user based on authentication credentials received from a client device. Validation data stored by the authentication device, and a corresponding access token transmitted to the client device, may be used to authenticate the user for future resource access requests. A user secret also may be stored by the authentication device and used to validate the user for future resource access requests. Additionally, after validating a user with a first set of authentication credentials, additional sets of credentials for the user may be retrieved and stored at an access gateway for future requests to access other services or resources in an enterprise system.