Newsletters outside of your inbox Letterun lets users view their favorite newsletters with an iOS or Android app, outside of their inbox. Illuminating newsletter spam while cleaning up the inbox for more personalized content. With a very friendly user interface they can save, explore and archive only what they want to see. Publishers can use their existing mail client for automatic publishing or create something new inside Letterun. No more having to give your readers instructions on how to keep out of the spam folder and it's easy to delete email mistakes from showing in the app.