In embodiments of cross device visitor correlation, application data is generated by an application executing on a computing device, and a visitor identifier is included in the application data. The visitor identifier is associated with the computing device for a user who is not identified at the computing device from a user-provided log-in credential or email address. The application data can be communicated to a cloud data storage that maintains the application data to update instances of the application on one or more additional computing devices when the application data is requested. An additional computing device can receive the application data along with the visitor identifier, and then return the visitor identifier back to the cloud storage along with updated application data. A user of the computing device and the additional computing device is correlated as the same visitor by a visitor profile server based on the visitor identifier.