Alien Blue, stylized as AlienBlue, was an iOS application for browsing Reddit developed by Jason "Jase" Morrissey.

Initially released in May 2010 on the App Store, Alien Blue rapidly became popular, soon overshadowing Reddit's own iReddit application.

In April 2016, citing an aging codebase, the app was discontinued and replaced with a rewritten official Reddit application for both iOS and Android.

Alien Blue featured a number of browsing and quality-of-life improvements over other apps and the Reddit website at the time, and was praised by users and critics throughout its lifespan.

[7] Reddit's head of partnership and strategic development (later interim-CEO) Ellen Pao said of the acquisition: "We want to be able to have new features from Reddit.com show up on mobile faster and better.

"[13]The "Alien Blue" branding was retained in the acquisition, but the subtitle "reddit official client" was added to the App Store listing.

[3] Following its acquisition, the application required a redownload for users, as the App Store binary was considered separate from the previous version.

[18] Then-vice president of product, Alex Le, cited customer confusion with the "Alien Blue" name in influencing the decision to delist the older app;[16] Reddit had previously indicated a desire to continue the Alien Blue branding at the time of acquisition.

[26] The iPad version was made free upon Reddit's acquisition of the app, and eventually phased out in favor of a universal binary.

Its appearance would have been similar to the iOS version, and shared the same Objective-C codebase, but would have featured a larger multi-panel interface.