Privacy
Last updated 30 August 2026
Aneroid is built on one decision made before anything else: there is no server where I can read your data. There's no account, no login and no analytics tools. What the app measures lives on your phone and in your own private iCloud — the same place as your photos and notes, under your Apple account, not mine.
This page describes both the app and this website. The two are separate and share no data.
The app
What it stores on the phone
| Data | Why | Where it lives |
|---|---|---|
| Air pressure with a timestamp | The measurement itself. One every five minutes. | The phone + your iCloud |
| Altitude above sea level | A pressure reading without altitude means nothing — one hPa is roughly 8.3 metres. | The phone + your iCloud |
| Your answers to “how are you feeling?” (1–5) | One half of the connection the app is looking for. | The phone + your iCloud |
Your answers about how you feel are health information. They're treated accordingly, as the sensitive data they are: they aren't sent to any third party, and there's no copy with me. The only copy beyond the phone lives in your own iCloud, as described below.
iCloud
The app stores its data in your private iCloud database. It's not a service I run, and I can't see the contents: it sits under your own Apple account, and access follows you — not me. I have neither account, key nor access path to it.
The reason is durability. Aneroid needs weeks of continuous measurements to say anything about you, and they mustn't disappear because a phone is lost, breaks or gets replaced. With iCloud they're still there on the next one.
If you don't have iCloud turned on, are logged out, or your storage is full, the app works exactly as before — it just keeps measuring locally on the phone. Syncing is a seatbelt, not a requirement.
If you want to delete your data, you can do it without going through me: under Settings → your name → iCloud you can both see what Aneroid takes up, and remove it entirely.
Location
Aneroid requires access to your location, and the app shows nothing without it. It's not to know where you are. It's because a pressure reading without altitude can't be compared to anything — not even your own reading from a different floor. Altitude is calculated on the phone itself by combining the barometer with GPS and Apple's terrain maps.
Your location is never sent anywhere by this feature. Neither coordinates, address nor route are stored — only one number: metres above sea level, together with how uncertain that number is.
Weather (optional, off by default)
The app can fetch temperature and humidity from Apple's weather service and show them on the two small dials. It's the only feature where anything leaves your phone, and it's therefore off until you turn it on yourself.
Turn it on, and your approximate location (accurate to about a kilometre) is sent to Apple Weather to fetch the weather for that place. Apple states that location data for WeatherKit isn't linked to your Apple account. Turn the feature off again, and the app stops sending immediately. See Apple's description of Weather data.
Other permissions
- Motion and fitness. Used solely to read the barometer. No steps are counted, and no activity data is stored.
- Reminders. Used to ask how you feel. All notifications are created on the phone — there's no push server.
- Background refresh. Lets the app take a measurement when it isn't open. Without it, the dataset fills with gaps.
What the app doesn't do
- No account, no login, no email address.
- No analytics, crash-reporting or advertising SDKs. No third-party code at all.
- No advertising ID, no fingerprinting, no profiling.
- No sale or sharing of data. There's nothing to sell — it isn't with me.
Your data is yours
- Export. Everything can be exported as a CSV file. You decide who you share it with — your doctor, for example.
- Deletion. Delete the app, and the local database goes with it. Remove the copy in your iCloud under Settings → your name → iCloud. There's no one with me to ask to forget you.
- Access. There's no data about you with me to give access to.
This website
The site counts visits, so I can see if anyone's reading. The counter runs on the server and leaves nothing on your computer — no cookies, no localStorage, no reading of your device. That's also why there's no cookie banner: there's nothing to ask consent for.
To tell two readers apart, a fingerprint is generated as sha256(today's secret key + IP address + browser string), shortened to 16 characters. The key changes every night and is never stored, so yesterday's fingerprint can neither be recreated nor linked to today's. Your IP address goes into the calculation and is then discarded — it's written nowhere.
What's stored is broad categories: which page was read, whether the visit came from a search engine or a link, whether the device is mobile or a computer, browser family, language and time of day. Never the full referring address, never the raw browser string. The numbers are counted per page and aren't combined across my domains into profiles.
The site loads no fonts, scripts or images from other domains. There are no embedded third-party services.
Controller and contact
Aneroid is a personal project. The data controller is Lars Sommer, Denmark. Questions — including critical ones — are welcome at hej@jegerlars.dk.
If you believe your information is being handled incorrectly, you can complain to the Danish Data Protection Agency (Datatilsynet).
Changes
Aneroid is under development, and this page changes along with the app. The date at the top says when it was last updated. If anything material changes — for example if data should ever become shareable — it will be stated here before it happens.