This project demonstrates how to login into a website using Persona in an iOS app. This can be used for authentication for an API, for example. The sample app will log into sloblog.io, which uses omniauth-browserid. The code has only been tested with this site and should be considered awesome, yet experimental.
You will need all the files with prefix BrowserID in your project. Make sure the JS is added as a resource and not as source code. Set the parameters of BrowserIDViewController to match those of the site you want to access. You will get one or more NSHTTPCookies back which you can use to make subsequent authenticated requests.