Introduction

Day1T1 is an advisory app that people with type 1 diabetes and their families use to log and follow their readings. This policy explains what we collect, why, who we share it with, and how to delete it.

Data we collect

• Account data: your email address (sign-in by a code sent to your email, or by password), and your password if you set one (the authentication provider stores it hashed, never in plain text; we never see it).
• Your profile: name, phone, date of birth, city and country, gender, occupation, weight and height, age at diagnosis, other health conditions you enter, treatment type and insulin doses, and the carb ratio, sensitivity factor and targets you entered. And your profile photo if you choose one: it is downsized on your phone, then kept inside your profile, so it syncs with your copy on our server and is restored with it.
• Health data you enter or import: glucose readings (typed in, from a Bluetooth meter, from a continuous glucose sensor you connect, or from a sensor file), meals & carbs, insulin doses, pens and injection sites, exercise, hypo events, DKA assessments, sick-day mode and their follow-up notes, lab results, medications, vitamins, water, sleep and mood, appointments, notes.
• Data about people you look after: if you create a profile for your child or a parent, their name and health data are kept and synced like yours, and your list of profiles (their names) is part of your copy on our server. If you link their email to that profile (Pro Plus), we send that address a consent email with your name, your email and a six-digit code; until the code is confirmed we keep only a hash of the address and of the code, deleted after a day. Once confirmed, an account is created for that email and linked to the profile.
• Companions: the email of someone you invite as a companion. We keep it in the invite so it appears in their app when they sign in with that address — we do not send them an invitation email. Once they accept, their email stays in the follow link so you can see who follows you. A companion sees your name as it appears in your profile and your latest reading (including your sensor's latest reading if you connect one), and receives the low alert (including a low your sensor reads while the app is open), the DKA risk alert, and very-high and high-carb-meal alerts if you turn those on. An alert carries your name, the glucose value for a low, and for DKA risk the fact that the assessment was high-risk and your latest ketone value if you measured one. We keep their device's notification token to deliver them.
• Bluetooth meter (when you connect one): we read only its readings, their times and their type. The meter's serial number is hashed on your phone, and only that hash is kept, inside reading ids, to avoid duplicates. The app sends no commands to the meter, and Bluetooth is used only to read it. On Android 11 and below the system requires the location permission for any Bluetooth scan, so it is asked for that alone — the app never reads or collects your location. The list of meters you have paired (the meter's name, model and Bluetooth identifier) is kept on this phone only and is not synced; the meter's readings enter your log and sync like the rest of your health data.
• Continuous glucose sensor (CGM), when you connect one (Pro Plus): the app reads your readings from your own Nightscout site, or from a CSV file you export yourself from your sensor's service (such as LibreView or Dexcom Clarity) and pick on your phone. Your site address and access token stay on your phone only: the token in the system's secure storage (Keychain on iPhone, Keystore on Android), and the address in the app's settings on the phone. Your phone sends them directly to your site alone to fetch your readings. They never pass through our server, are not part of the sync copy, and are sent to no one else. The app does not connect to Abbott or Dexcom services.
• Sensor readings: kept in a separate database on your phone for 14 days, per profile, and not part of the sync copy. The app fetches them only while it is open. If you have a companion, the app sends your latest sensor reading and its trend to our server in the status snapshot your companions see, at most once every five minutes while readings arrive, and each snapshot replaces the previous one. If the sensor reads a low and an alert goes to your companion, the glucose value is kept in the alert record. What enters your log from them, meaning a reading you save when you log a reading, meal, exercise or hypo, and the days you import from a CSV file, becomes part of your health data and syncs with your account like the rest.
• What you send to the smart features (after you agree): food photos or descriptions, the lab photos or PDF files you upload, and your questions to the assistant — see "AI" below. They pass through our server and we do not keep them.
• Barcodes: the barcode number you scan, which your phone sends to Open Food Facts only.
• Free-trial abuse prevention: a one-way salted hash (SHA-256) of your device identifier and of your email, with the number of trial requests used. To confirm the device is genuine, we send a token generated by your phone to Google Play Integrity or Apple DeviceCheck. To limit many trial accounts from one network, we keep a hash of your network address (not the address) salted with the day, deleted after two days.
• AI request counter: how many requests you have used, to apply your plan's limit.
• Subscription (when you buy one): the purchase receipt we receive from Google Play or the App Store (the product, the purchase token and its hash, the transaction id or order number, the platform, and the expiry date), the store's renewal, cancellation or refund notices, and your current plan and its expiry, to activate and verify your subscription and stop a receipt being reused. We never receive your card or payment details.
• The last day you opened the app: once a day the app records on our server the date (not the time) and whether you have finished setup (your carb ratio is set). We use it only to know how many people keep using the app; nothing about what you did in it or where you were is recorded.
• Crash reports: when the app crashes it sends a technical report to Firebase Crashlytics, with email, identifiers and health values removed.
• Voice input (when used): your phone's speech-recognition service (from Apple or Google) turns your voice into text. We do not receive or keep the audio.
• Notifications: reminders are scheduled on your device. While you are signed in, we keep your device's notification token, its platform and the app language, so alerts meant for you, such as those from someone you follow as a companion, reach you in your language.

How we use it

To run the app's features: logging, advisory calculations, reminders, reports, sync between your devices, companions and profile management, and the smart features you request; to prevent repeated free trials; and to know how many people keep using the app (the date of the last open only). We do not sell your data, do not use it for advertising, and show no ads.

Where data is stored

• Locally on your device (on-device database).
• On our server (Supabase): while you are signed in, your health records and your profile — including your name and your profile photo if you set one — are synced to your account automatically, together with the profiles of people you look after and their names, and the sensor readings you confirmed, so everything comes back on a new phone. Also account, subscription and companion data (including your name in the status snapshot, and the emails of people you invited or whose email you linked). No one else reaches it except those you choose: a parent who linked your profile to your email sees and logs in your record while that management lasts, and a companion you invite sees only your latest reading and the alerts you allow. Storage is encrypted at rest and transport uses HTTPS; this is not encryption with your own password.
• What you send to the AI features passes through our server to Google Gemini to carry out your request only, and is not kept on our server.
• A backup file you export yourself can be password-protected (AES-256-GCM).

AI (Google Gemini)

The smart features — meal photo or description analysis, reading a lab report (photo or PDF), the assistant, smart summaries, pattern analysis explanations and the eating plan — send, through our server, to Google's Gemini service:

• the meal photo or description and weight;
• the lab report photo or file as it is, which may show your name and file number;
• your question and the last messages of the conversation, with a numeric summary of your data (average glucose, time in range, number of lows and highs, insulin on board, the names of your medications, your latest labs);
• the aggregated numbers behind summaries, and the pattern-analysis findings worked out on your phone (not your readings themselves) when you ask for them to be explained;
• for the eating plan: age, sex, weight, height, goal, the other health conditions you entered in your profile, and a 14-day readings summary (average, number of readings, lows and highs) — no insulin doses.

Nothing is sent before you agree on a screen shown once before your first request, and you can change your choice at any time in Settings → App → "Smart features & your data". Photos, files and text are sent to carry out the request only and then discarded; we do not store them on our servers. Values you save from a result become part of your health data. We use Google's paid service, under which Google does not use this data to train its models.

Data retention

We keep each kind of data only for the period set out below:

When you delete your account, every row linked to it is erased from our servers in the same operation, and your cloud backup files are deleted within minutes. Only what is described above as kept remains: the trial abuse-prevention hashes, the receipt record, store notices until their period ends, and the bounced-email hash — none of them carries your email or your health data. What the store (Google Play or the App Store) keeps about your purchases is governed by its own policy.

Third parties (processors)

We do not sell your data and share it with no one beyond those listed here, each for a stated purpose:

CSV files you export from LibreView (by Abbott) or Dexcom Clarity (by Dexcom) are read on your phone; the app does not connect to those services. Day1T1 is not affiliated with Nightscout, Abbott or Dexcom; all names are trademarks of their owners. We disclose your data to no one else except under a binding legal order.

Some of these services operate servers outside Egypt, so using the app involves a cross-border transfer of data.

Children

Day1T1 is not directed at children on their own. Account holders must be 16 or older. A parent can follow a child in a profile inside the parent's account, or link the child's email to that profile (Pro Plus) so the child logs from their own phone with the parent's consent and supervision, and the parent sees what they log. A parent can ask us to delete a child's data at any time by emailing support, or by deleting the profile or account.

Your rights — account & data deletion

You can permanently delete your account and all data in the app: Settings → Advanced → "Delete account & data". This erases your data from your phone and our server, the synced copies, and the sensor data on the phone, and cannot be undone — except what is described above as kept. You can also use the account-deletion page, or email support. You can delete any single record without deleting your account.

Changes

We may update this policy and will post changes, with their date, at the same URL. If what is sent to the AI provider, or to whom, changes, the app will ask for your consent again.