NightStand privacy policy

What the app records

Phone movement. The app reads the iPhone's motion sensor and keeps 30-second summaries of how much the phone moved.
Sleep from Health. If an Apple Watch writes sleep to the Health app, the app reads those sleep records to show your nights. Nothing else is read from Health, and nothing is written to it.
Morning check-ins. Your rating of the night, your guesses of when you fell asleep and how long you slept, your answers to four short questions about the night, and the night the app then showed you.
Tests. The results of the 30-second tests you take, in the morning check-in, the evening check-in or any time.
Charging and battery. When the phone is plugged in or unplugged, and the battery level.
Screen lock state. When the phone is locked or unlocked while the app is running.

Location. If you allow it, the app uses the iPhone's location service only to keep running in the background, so the night's recording has no gaps. It does not store your location, and you can turn this off in the app's Settings at any time.

The app does not record which apps you use or what is on your screen. It has no account and asks for no name or email.

Where it stays

On your phone, unless you take part in our study and turn on sharing. Without sharing the app sends nothing to us or to anyone else.

Sharing with our study

We study sleep and phone use. If you take part, you receive a study code. On the app's first page and in its Settings, under Have a study code?, you can enter the code and turn on Share my data with the study. It is off until you turn it on.

What is sent while sharing is on. The data listed above, with your phone's model, iOS version, app version, time zone and language setting, and the token that lets our server reach the app. Your location is never sent.
How it is identified. By your study code only. The app asks for no name or email.
Where it goes. To our study's database, hosted by Supabase in the United States, over an encrypted connection. Only the study team can read it.
What it is used for. Research on sleep and phone use. We may share it with other institutions for research. We do not sell it and do not use it for advertising.
How long the study lasts. Two weeks. Sharing continues until you turn the switch off.
Risks and benefits. There are no foreseeable risks beyond those of everyday life. We do not promise you any benefit. Your data help us answer questions about sleep and phone use.
How long we keep it. For as long as the research needs it, or until you ask us to delete it.
Stopping. Turn the switch off and the app stops sending at once. Data sent before then may still be analysed.
Deletion. Write to the address below with your study code and we delete what you shared.

Taking part is voluntary. The app works the same with sharing off, except that the reaction test in the morning check-in can be skipped only while sharing is off.

Exporting your data

Settings has an Export button. It writes a file with your nights, hourly movement and unlock counts, check-ins and test scores. The file goes only where you send it.

Background activity

With location allowed, the app keeps running in the background. Otherwise iOS wakes it briefly now and then so it can keep recording movement. While sharing with our study is on, our server also wakes it with a silent notification so that it can send the data. None of these shows anything on screen. While sharing is on we may also send a notification that asks you to open the app.

Your choices

Permissions. Movement, sleep from Health, location and notifications each have a switch in the app's Settings. The iOS permissions can also be withdrawn at any time in the iPhone's Settings. The app then reads nothing from those sources.
Deleting your data. Delete the app. Everything it kept on the phone is deleted with it. For data shared with our study, see Deletion above.
Questions. Write to [email protected].