Twilight: Blue light filter

421K reviews
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Content rating
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About this app

Are you having trouble falling asleep? Are your kids hyperactive when playing with the tablet before bed time?
Are you using your smart phone or tablet in the late evening? Are you sensitive to light during migraine?
Twilight may be a solution for you!

Recent research suggests that exposure to blue light before sleep may distort your natural (circadian) rhythm and cause inability to fall asleep.

The cause is the photoreceptor in your eyes, called Melanopsin. This receptor is sensitive to a narrow band of blue light in the 460-480nm range which may suppress Melatonin production - a hormone responsible for your healthy sleep-wake cycles.

In experimental scientific studies it has been shown an average person reading on a tablet or smart phone for a couple of hours before bed time may find their sleep delayed by about an hour. See references below..

The Twilight app makes your device screen adapt to the time of the day. It filters the flux of blue light emitted by your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times.

You can also use Twilight on your Wear OS device.


Get more from Twilight
1) Bed reading: Twilight is more pleasant on the eyes for night reading. Especially as it is able to lower the screen backlight far below the ability of the backligt controls on your screen

2) AMOLED screens: We have tested Twilight on an AMOLED screen for 5 years without any sign of depletion or over-burning. If properly configured Twilight causes less light emission (by enabling dimming) with more equal light distribution (dark areas of the screen such as the status bar get tinted). This may in fact increase your AMOLED screen life time.

Basics on circadian rhythm and the role of melatonin

- location - to find out your current sunset/surise times
- running apps - to stop Twilight in selected apps
- write settings - to set back-light
- network - access smartlight (Philips HUE) to shield you household light from blue

Accessibility Service

In order to filter also your notifications and lock screen the app may ask for enabling Twilight Accessibility Service. The app uses this service only to better filter your screen and does not collect any personal information. Please read more about this at

Wear OS

Twilight also syncs your Wear OS screen with your phone's filter settings. You can control filtering from a "Wear OS Tile".

Automation (Tasker or other)

Related scientific research

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans Derk-Jan Dijk, & Co 2012

Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans Joshua J. Gooley, Kyle Chamberlain, Kurt A. Smith & Co, 2011

Effect of Light on Human Circadian Physiology Jeanne F. Duffy, Charles A. Czeisler 2009

Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans Claude Gronfier, Kenneth P. Wright, & Co 2009

Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans Kenneth P. Wright, Claude Gronfier & Co 2009

The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work Nayantara Santhi & Co 2008

Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina Farhan H. Zaidi & Co, 2007
Updated on
Oct 20, 2023

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection

Ratings and reviews

393K reviews
Adrian Oliva
November 29, 2023
I love it, it does what it is supposed to do: protect your eyes. I only don't know why sometimes the wall paper remains shaded in red hues after I turn off the filter. other than that, VERY good app ------ The wallpaper filter option IS enabled but it should go back to normal once the app is paused right? In any case, if I change the wallpaper it goes back to normal.
1 person found this review helpful
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Urbandroid (Petr Nálevka)
November 29, 2023
UPDATE: Hello Adrian, unfortunately wallpaper filtering is no more possible on Android 14+.. Google did remove access to wallpaper image to 3rd party apps for security reasons. Sorry about the limitation. For details please contact Petr
Christine Hanley
November 14, 2023
I think it helps since I like to play some solitaire and other games right before I go to sleep. It's easy to adjust the times that you wanted to dim and the intensity of the colors etc. Also there's a quick little guy icon at the bottom right hand corner of my screen that allows me to shut it off quickly if I need full light. I don't see anything more they need to improve.
3 people found this review helpful
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Suzette Susanne
September 14, 2023
This app is easy to use and I believe it helps a lot. I like the fact that it's very adjustable. You can make a different setting for different applications on the phone... So if you want to have one app that you see in full 'regular' color, but have everything else on the blue blocking setting, you can do that.
27 people found this review helpful
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What's new

- Proper Wear OS 3+ support + Wear OS Tile