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Popular screen brightness app f.lux is now available for iOS

Popular screen brightness app f.lux is now available for iOS

November 11, 2015

Have you ever noticed your eyes straining when you use your iPhone or iPad at night? Or, do you see an eerie blue glow when you watch people texting at night? During the day, your iPhone screen looks great, because it’s designed to look like the sun. At night, though, looking at the sun isn’t such a good idea. That’s where f.lux comes in, a free app that makes the color of your iPhone or iPad display adapt to the time of day. Not only that, but the app includes a Darkroom mode for working late, late at night


Getting f.lux

F.lux has been available for Macs for quite some time, but it’s brand new to iOS. Since the app requires access to private APIs that Apple doesn’t allow developers access to, though, you’ll have to sideload f.lux onto your iOS device using Xcode 7 and a Mac running OS X 10.10 Yosemite or later. Here’s how to make it all come together.

Sideloading f.lux

F.lux has provided detailed instructions for how to sideload the app on your iPhone or iPad. The first thing you need to do is make sure you have Xcode 7 installed from the Mac App Store. Then, follow these instructions.

  1. Download f.lux for iOS, unzip, and open the “iflux.xcodeproj” project in Xcode. It’s a free download.
  2. Open Xcode > Preferences > Accounts and enter your iCloud or developer credentials.
  3. Under Targets > iflux > General > Identity, add a word to the end of the Bundle Identifier to make it a unique name.
  4. In that same place, under Identity > Team, select your iCloud account or Developer profile

Next, you’ll connect your iOS device to your Mac using a Lightning cable, and follow these steps.

  1. From the Xcode Product menu, choose Destination and select your iOS device.
  2. Press Cmd-R when you’re ready to install f.lux.
  3. When you first run the app, you’ll be prompted to open Settings > General > Profile on your iOS device, and trust your developer account.
  4. Run the app again, and allow both location and notifications.

When you sideload an app, you don’t get automatic updates. What f.lux does to allow for updates is check every day. If there is an update available, you’ll get a message at the bottom of the app, so you can keep your copy of f.lux up to date with the latest fixes.


F.lux is a great way to optimize your screen to your eyes based on the time of day. You will notice that it generates quite a few notifications, because that’s how it changes the screen brightness, but those minor inconveniences should be worth giving your eyes more of a rest when you use your device early in the morning or late at night. If the notifications are too much hassle, though, the app provides another way to adjust the brightness by prompting you to unlock your screen.

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