Some systems allow a user to access content using both a native client application and a web interface. In these systems, the client application authorized to access a user account can assist with automatically logging a user into the web interface through the use of authentication tokens. In response to an authentication request, the client application can select a token and split it into multiple parts. One piece can be embedded in a URL and a second piece can be stored in a file. The file can also contain browser executable instructions that when executed combine the two pieces to re-create the token and send the re-created token to a server to authenticate the user. The client application can forward the URL to the browser, which can direct the browser to the file. The browser can execute the instructions thereby authenticating the user.