Crybell Privacy Policy

Version 1.2 · Effective from 2026-10-31

This policy explains what happens to information when you use Crybell, the Android app (com.morph21.crybell) that listens for a baby's crying and wakes a parent with a notification or an alarm. Polish version: Polityka prywatności.

1. Who is responsible

The controller of personal data described in this policy is:

Krzysztof Gruszczyński APP
ul. Powstańców Śląskich 176/30
53-139 Wrocław, Polska (Poland)

E-mail: crybell.app@outlook.com

We have not appointed a data protection officer. Write to the address above with any question about this policy or your data.

2. In short

• Sound from the microphone is analysed only on your phone, in real time. It is never sent to us or to anyone else.
• Your baby's profile, the listening history, your labels and your log of feeds, sleep and diapers stay on your phone. Crybell has no accounts you sign in to and no server of its own, so we cannot see this data.
• The exception: if you turn on the shared log, this data goes through Google Firebase to the phones you connect. It is end-to-end encrypted on your phone, so neither we nor Google can read it (section 7).
• Nothing from your baby's log, the crying episodes or your labels is passed to the ads, crash-report or payment services.
• The free version shows ads from Google AdMob. Google receives some device data for this. Where the law requires it, we ask for your consent first.
• Crash reports go to Firebase Crashlytics. You can turn them off in the app.
• Premium is bought through Google Play. We never see your card details.

3. Microphone and sound

Why the microphone. Crybell needs the microphone to notice crying while you sleep. It listens only after you tap Start (in the app, on the Quick Settings tile, on the widget or in the bedtime reminder) and stops when you tap Stop. While it listens, Android shows a permanent notification.

How sound is processed. A sound model on your phone (YAMNet) scores short pieces of audio, about one second each. For this, the audio is held only in the phone's working memory, and it is discarded straight after. The part of the app that listens runs separately from the rest of the app and does not connect to the internet.

Cry clips (Premium, optional). If you turn on clips (they are off by default), Crybell saves about 10 seconds of sound around the start of each crying episode that led to an alert, so you can play it back. Clips:

• are stored only on your phone, in a folder that is excluded from backup and from transfer to a new phone;
• never appear in your gallery or media library and are never uploaded;
• are deleted automatically after the period you choose (24 hours, 7 days or 30 days; 7 days by default);
• can be deleted at any time with "Delete all clips".

4. Information stored on your phone

Crybell stores the following on your phone, in the app's private storage:

• your baby's profile: the date of birth, and optionally a name, the due date and the feeding method;
• listening sessions: start and end, the alarm profile and sensitivity, and interruptions with their cause;
• crying episodes: times, the total crying time, how loud it was compared with the background, the alert stage reached, how quickly you responded, your label ("what helped"), your note and whether you marked it as "not crying";
• your log: feeds (breast side or bottle amount), sleep and diapers;
• if you turn on the shared log: the names of this phone and of the connected phones, and the keys with which the phone encrypts and reads the shared log;
• settings, and a record of when you accepted the microphone notice, these documents and the shared log (date and text version).

This information is used only to run the app's features: the history, the morning summary, the suggestions and the statistics. It stays on your phone and is not sent to us. Some of it describes your baby's daily routine; this is one reason Crybell never sends it unencrypted. The exception is the shared log, if you turn it on: an encrypted copy then goes to the connected phones (section 7).

Before it listens for the first time, Crybell asks for the baby's date of birth, because the suggestions and statistics depend on the baby's age. The name, the due date and the feeding method are optional; you can add them later in Settings. Without a profile, Crybell does not start listening.

Crybell makes no decisions about you that have legal or similarly significant effects. Its suggestions are computed on your phone from your own log.

5. Android backup and moving to a new phone

If Android backup is turned on, Android may include Crybell's database and settings in the backup kept in your Google account, and restore them when you set up a new phone or transfer data from the old one. This backup is provided and governed by Google and by your phone's settings; we have no access to it. Cry clips and audio buffers are always excluded, and so are the shared log's keys. You can turn backup off in your phone's settings (usually Settings → System → Backup).

6. Export and import

You can export your history and log as CSV or JSON files through Android's share menu. You choose where the file goes; we do not receive it. An exported file contains your log, so keep it safe. Import reads only a file you pick. On a phone connected to a shared log, imported entries also go to the shared log.

7. Shared log

What it is. The shared log is optional and free: the same baby log shows on 2 to 4 phones, for example yours, the other parent's and a nanny's. You turn it on in Settings ("Shared log"): one phone shows a code, the other scans it. Until someone taps "Show code" or "Scan code" on a phone, nothing in this section happens on it.

What is sent. The baby's profile (the date of birth, and optionally a name, the due date and the feeding method), the log entries, the crying episodes with their times, your labels and notes, the listening sessions with their interruptions, and the name of each connected phone (its model by default; you can change it). When phones connect, they also send encrypted full copies of their logs, so that the histories can be merged. Not sent: sound or cry clips, the app's settings, Premium and the consent records. The alarm rings only on the phone that is listening; Crybell does not send alerts to other phones.

Encryption on the phone. Crybell encrypts all of this on your phone, before it goes to the internet (end-to-end encryption). Only the connected phones have the key; neither Google nor we have it, so we cannot read the shared log. The server sees only that a shared log exists, how many phones it has and their random identifiers, how many times the key changed (that is, how many times a phone left or was removed), when the phones send changes and roughly how large the encrypted data is.

Where and by whom. Google Firebase services:

• the encrypted log is stored in Google Cloud Firestore in the Warsaw region (europe-central2); Google states that the service may also process data in its other locations, for example in transit;
• Firebase Authentication: each connected phone signs in anonymously, without a name, an e-mail or a password, and gets a random identifier (uid). With it, the server lets in only the connected phones, keeps the limit of 4 phones and cuts off a phone removed from the list. Firebase Authentication runs in Google's data centres in the United States: this identifier and the phone's IP address go there, and Google keeps the IP address in its logs for a few weeks;
• Firebase App Check checks that it is the real Crybell app that connects to the server; in the version from Google Play it uses Play Integrity for this, which assesses the app and the device.

In these services Google acts as our processor, under the Firebase data processing terms. The code is read by the Google code scanner (ML Kit, in Google Play services): Crybell gets no access to the camera or the image, and Google receives information about the device and the app, installation identifiers and performance data.

How long. Changes to entries and full copies stay on the server for at most 14 days, then they are gone; the full history is only on the phones. A connection code works for 10 minutes and only once. The list of connected phones, their encrypted names and the keys expire after 90 days without activity, so a log abandoned on every phone disappears from the server by itself. Removing expired data can take up to a day longer.

Disconnecting and deleting. "Disconnect this phone" at once removes this phone from the list of connected phones and deletes its document on the server (without internet: the next time it is online); the phone keeps its log up to that moment. If the connection data on the phone is damaged, the phone disconnects only on its own side: another phone removes its place on the list, or it expires after 90 days without activity. The changes it sent before stay for the other phones and expire within 15 days. When the last phone leaves, it deletes every document of the shared log except the encrypted pieces of full copies, which expire within 15 days. "Delete all data" on a connected phone disconnects it first (without internet: the next time it is online). When a phone leaves, Crybell also deletes that phone's anonymous Firebase account. If this fails, the account is left without any data, or, when the connection data was damaged, with only its place on the list until another phone removes it or it expires. Any connected phone can remove another phone from the shared log: the removed phone keeps its log up to that moment but gets no new entries.

Invite people you trust. Every connected phone sees the whole baby log, can change it and can remove another phone. Show the code only to people you want to connect. If someone should no longer see the log, remove their phone on the shared log page.

Legal basis: performing the contract (Article 6(1)(b) GDPR), that is, running the feature you turn on. Your baby's log may contain information about the baby's health, so we also send it on the basis of your explicit consent (Article 9(2)(a) GDPR). You give it with your first tap on "Show code" or "Scan code" on the shared log page, where the line under these buttons says so; the phone records it with the date and the version of this policy. You withdraw it by disconnecting the phone ("Disconnect this phone"); this does not affect sending before the withdrawal.

8. Ads (Google AdMob) and your consent (Google User Messaging Platform)

Where ads appear. The free version shows banner ads on the history, statistics and settings screens, and at most one full-screen ad a day, in the morning after you stop listening. Crybell never shows ads on the listening or alarm screens. With Premium, the app does not request ads.

Who provides them. Ads are served by Google AdMob (Google Ireland Limited for users in the European Economic Area and Switzerland, Google LLC elsewhere). The Google Mobile Ads SDK in the app collects and shares with Google:

• your IP address, which Google may use to estimate your approximate location;
• the advertising ID, the app set ID and other device identifiers;
• interactions with ads, such as views and taps;
• diagnostic information, such as app launch time and performance.

Google uses this information to show and measure ads, to analyse how ads perform and to prevent fraud and abuse. Google describes this at <https://policies.google.com/technologies/partner-sites> and in its privacy policy at <https://policies.google.com/privacy>.

Consent. In the European Economic Area, the United Kingdom and Switzerland, Google's User Messaging Platform shows a consent form at the end of the app's setup. Personalised ads are shown only if you agree. If you do not agree, Google may show non-personalised or limited ads, which still use some information, for example to limit how often an ad is shown and to prevent fraud. You can change your choice at any time in Settings → Privacy → "Ad privacy settings".

Advertising ID. You can reset or delete the advertising ID in your phone's settings (Settings → Privacy → Ads, or Settings → Google → Ads).

Legal basis. Personalised ads and storing or reading information on your device for ads: your consent (Article 6(1)(a) GDPR). Non-personalised ads, frequency limits and fraud prevention: our legitimate interest in funding the free version and in preventing abuse (Article 6(1)(f) GDPR), within the choices you make in the consent form.

9. Crash reports (Firebase Crashlytics)

To fix crashes and make night listening more reliable, the app sends crash reports to Firebase Crashlytics, a Google service. A crash report contains the error and the app's state at the time of the crash, the phone model, the Android version and a random Crashlytics installation ID.

When listening was interrupted unexpectedly (for example, because the system closed the app), the app also sends one anonymous event with the cause, the phone's manufacturer, the Android version and how long the gap lasted. Crash reports never contain your baby's data, your log, episodes, labels, notes or any sound.

Google keeps crash data for 90 days. Crybell does not use Google Analytics for Firebase.

Legal basis: our legitimate interest in a reliable, working app (Article 6(1)(f) GDPR). You can object at any time by turning off Settings → Privacy → "Send crash reports".

10. Purchases (Google Play Billing)

Premium is a one-time purchase made through Google Play Billing. Google processes the payment under its own terms and privacy policy; we never receive your card or bank details. The app receives from Google Play only the status of your purchase and a purchase token, which it keeps on your phone to unlock Premium and to restore it on another phone. Google gives us the order details we need for accounting, refunds and taxes (such as the order number, the product, the price, the country and the date).

Legal basis: performing the contract (Article 6(1)(b) GDPR) and our legal obligations in accounting and tax law (Article 6(1)(c) GDPR).

11. Children

Crybell is meant for adults: parents and caregivers. It is not directed to children, and we do not knowingly collect personal data from children. The information you enter about your baby is stored on your phone, as described in sections 4 and 5; if you turn on the shared log, also on the connected phones, and on its way between them only end-to-end encrypted (section 7). It is not collected by us and is not passed to the ads or crash-report services.

12. Permissions the app asks for

• Microphone (RECORD_AUDIO) and the foreground service for the microphone: to listen for crying after you tap Start.
• Notifications (POST_NOTIFICATIONS): for the listening notification, cry alerts, warnings and the morning summary.
• Full-screen alerts (USE_FULL_SCREEN_INTENT): to show the alarm over the lock screen, if you allow it.
• Vibration (VIBRATE) and run at startup (RECEIVE_BOOT_COMPLETED): to vibrate on alerts, and to tell you after a restart of the phone or an app update that listening has stopped. Crybell does not start listening by itself then: it asks you to resume.
• Internet and network state (INTERNET, ACCESS_NETWORK_STATE), advertising ID (AD_ID) and Google Play Billing (BILLING): for ads, crash reports, purchases and the shared log only. The listening part of the app does not use the internet.

The flashlight blink option uses the camera flash without access to the camera itself. The shared log's code is read by the Google code scanner, so Crybell does not ask for camera access.

13. How long information is kept

• On your phone: until you delete it. "Delete all data" in Settings removes the history, the log, the clips and the settings, and first disconnects a connected phone from the shared log; "Delete all clips" removes only the clips. If you uninstall Crybell, Android deletes all of its data from the phone. A copy in Android backup is kept according to Google's backup rules.
• Shared log: changes and full copies for at most 14 days, a connection code for 10 minutes, the list of connected phones and the keys for up to 90 days after the last activity; removing expired data can take up to a day longer (section 7).
• Ads: Google keeps ad data according to its own retention rules (<https://policies.google.com/technologies/retention>).
• Crash reports: 90 days.
• Your e-mails to us: as long as we need to answer and handle your matter, and then until claims related to it expire.

14. Your rights

Under the GDPR, you have the right to access your personal data, to have it corrected or erased, to restrict its processing, to receive it in a portable format, and to object to processing based on legitimate interest. Where processing is based on consent, you can withdraw it at any time; this does not affect processing before the withdrawal.

The shared log's entries (sections 4 to 7) reach its server only end-to-end encrypted (apart from the technical data listed in section 7), and the shared log's random identifiers do not name you, so we cannot find your shared log. That is why you exercise most of these rights directly in the app: export gives you a copy of your data, "Delete all data" erases it, and "Disconnect this phone" stops the sending and removes this phone from the shared log on the server. For ads, use "Ad privacy settings" in the app and the advertising ID controls on your phone. For anything else, write to crybell.app@outlook.com.

You can also lodge a complaint with a supervisory authority. In Poland this is the President of the Personal Data Protection Office (Prezes Urzędu Ochrony Danych Osobowych, UODO), ul. Stawki 2, 00-193 Warszawa, <https://uodo.gov.pl>. You can also contact the authority in the country where you live or work.

15. Transfers outside the European Economic Area

Google may process the information described in sections 8 to 10 outside the European Economic Area, including in the United States. This also applies to the shared log (section 7): Firebase Authentication runs in the United States (a random identifier and the phone's IP address), and the Google code scanner and App Check may process information about the device and the app outside the European Economic Area; the encrypted log is stored in Warsaw. Google relies on the EU–US Data Privacy Framework and on standard contractual clauses approved by the European Commission.

16. Security

Data on your phone is kept in the app's private storage, which other apps cannot read. Data sent by the Google services is encrypted in transit. The shared log is also end-to-end encrypted: on your phone, with a key that only the connected phones have (section 7). Keep your phone locked with a PIN, pattern or password, and keep exported files safe.

To report a security vulnerability, write to crybell.app@outlook.com. Our security contact is also published at https://crybell.pages.dev/.well-known/security.txt (security.txt).

17. Changes to this policy

We will update this policy when the app or the law changes. The version and the effective date are shown at the top. If a change matters for your data, the app will tell you before it takes effect.

18. Contact

Krzysztof Gruszczyński APP
ul. Powstańców Śląskich 176/30
53-139 Wrocław, Polska (Poland)

E-mail: crybell.app@outlook.com