Privacy Policy
This policy covers the Crypto Alerts & Alarms mobile app on Android and
iPhone (store id com.appsfromzero.sentinel on both) and this website.
It is written to be read, not to be survived.
The short version. You can use the app without giving us an email address. Your alerts are still watched on our servers rather than on your phone — that is what lets them fire while the app is closed — so the app creates an anonymous account for your device the first time it opens. We hold that account, the alerts you create, and a push token for your device; an email address only if you choose to add one. We use two analytics services to see where the app is confusing, and one of them records your in-app screens, with the sign-in and sign-up screens masked. We never ask for an exchange API key, a wallet key or a card number, and we do not sell anything about you. On Android we read your device's advertising identifier for one purpose — telling an install that came from an ad from one that did not — and you can switch it off in settings. On iPhone we read none. You can delete the lot from inside the app, or by emailing us.
1. Who we are
Crypto Alerts & Alarms is built and operated by Apps From Zero. We are the
data controller for everything described here. Our app backend runs at
sentinel.appsfromzero.com. You can reach us at
support@appsfromzero.com.
The app is published on Google Play and on the App Store, under the id
com.appsfromzero.sentinel on both. It was previously listed as Sentinel;
the name changed, the app and the account behind it did not.
2. What we collect, and why
| What | Why |
|---|---|
| An account id (a random identifier), created on first launch | Ties your alerts, history and subscription together. This is created without asking you for anything — it is what lets you use the app without signing up, and it holds no name, email or device fingerprint. It is shown to you in Settings › Privacy so you can quote it in a support or deletion request. |
| A session key held on your phone | Proves this device owns that anonymous account, so you stay signed in without a password. On Android it is deliberately excluded from backup, which is why an unconnected account does not follow you to a new phone. Do not count on a backup to carry it. |
| Your email address — only if you connect an account, by typing one or using Google or Apple Sign-In | Optional. It attaches credentials to the anonymous account you already have, so your alerts survive a lost or replaced phone, and it is how we reach you about a subscription, a refund or a security matter. Skip it and we never have one. If you use Apple's Hide My Email, the address we hold is the relay Apple gives us rather than your own. |
| Your password, if you connected an account without Google or Apple | Stored only as a one-way hash. We cannot read it, and neither can anyone who obtains the database. |
| The alerts you create — the pair or token mint, the level, the direction, the delivery channel, the repeat setting, whether it is on | Your alerts are evaluated on our servers against live prices. That is the whole product: it is what lets an alert fire when the app is closed, the phone is asleep, or you have changed devices. |
| Notification history — which alert fired, when, and at what price | So you can go back and read what happened. Shown in the app's History screen. |
| A push token and a device identifier | Required to deliver a notification to your specific phone. The device identifier is generated by the app; it is not your advertising ID, IMEI or serial number. |
| Subscription state — which plan you hold, when it renews or ends, your purchase history | To unlock the features you paid for and to answer questions about billing. Payment is taken by Google Play or the App Store; we never see your card details. |
| Your Telegram account id and username — only if you link Telegram | To deliver alerts you have routed there. Unlink the channel in the app and we delete it. |
| Feedback you send us, and the answer you pick in the cancellation survey | To fix what is broken and to understand why people leave. Sent only when you submit it. |
| Usage analytics — see section 3 | To find where people get stuck. |
| Where your install came from — on Android, your device's advertising identifier and the Google Play install referrer. Nothing on iPhone or iPad. | To tell whether a download came from an ad we paid for or arrived on its own. See section 4 — this is the one thing here used for advertising purposes. On Android you can turn it off in settings. |
| Ordinary server logs — IP address, timestamp, which endpoint was called | Security, abuse prevention and debugging. Kept short-term and not used to build a profile of you. |
Price data
The app does not talk to exchanges directly. It asks our backend, which fetches public market data from Binance, Coinbase, Kraken, Bybit and KuCoin, and on-chain data for Solana tokens. Nothing about you is sent to an exchange or to a blockchain — we ask for a public price, not for anything belonging to you.
3. Analytics and session recording
We run two analytics services over the same set of events, because two independent records can be checked against each other and one cannot.
- Firebase Analytics (Google) receives usage events — screens opened, an alert created, a paywall seen, an error shown — along with your account id and general device and app properties. Your email address is never sent to Firebase.
-
PostHog receives the same events, hosted in the European Union
(
eu.i.posthog.com). If you have connected an account, your email address is attached to your PostHog person record, so that we can exclude our own test accounts and so a deletion request is one record rather than a sweep through every event you ever generated. Without a connected account there is no email to attach, and the person record carries only the account id.
Session recording — please read this one. PostHog records your in-app sessions: a reconstruction of the screens you saw and where you tapped. It is how we found that people were abandoning the alert form, and which error message was stopping them.
The sign-in and sign-up screens are masked, so your email address and password are not captured in a recording. Everything else in the app is visible to us — which coins you looked at, the levels you typed, the errors you hit. The app shows public market data and your own alerts; it never displays a card number, a wallet key or an exchange credential, because it never has one.
Recordings are kept in PostHog's EU region. If you would rather not be recorded, email support@appsfromzero.com with your account id and we will exclude you.
We use the same events to run feature flags — switches that let a feature be turned on for some accounts and not others while it is being tested.
4. Advertising ID and install attribution (Android)
We advertise the app. To know whether that money does anything, we have to be able to tell an install that came from an ad from one that arrived on its own. On Android we do that. On iOS we do not do it at all.
- On iPhone and iPad, the app reads no advertising identifier. There is no IDFA, no measurement partner in the app, and no tracking permission prompt — because there is nothing to ask you about. If that ever changes, iOS will ask you first, and this page will say so before the change ships.
- The Google Play install referrer is read once, on first launch, and on Android only. It says whether you arrived organically or through a tagged link. It is not personal to you. iOS has no equivalent and we read none.
- Singular is a mobile measurement partner, and it is in the Android app only. The large ad networks (Meta, TikTok, Reddit, X, Snap) match an install on their own servers and will only report the result to an approved partner, which is what Singular is. On Android it receives your advertising ID, the install referrer, and app events such as a signup or a subscription, so a campaign can be credited.
This is the only purpose for which we use an advertising identifier, and it is the only thing in this policy that counts as advertising use. We do not show ads in the app, we do not sell your data, and we do not build an advertising profile of you. Singular is the only service that receives the identifier — our analytics providers do not.
On Android you can switch it off at any time in Settings › Privacy › Ads › Delete advertising ID. The app carries on working exactly as before — only our ability to credit a campaign is lost. On iOS there is nothing to switch off.
5. What we never collect
- Exchange API keys or exchange logins. The app cannot place a trade and has no mechanism to try. It is never going to ask.
- Wallet private keys or seed phrases. There is no wallet in this app. A Solana mint address is a public identifier for a token, not for you.
- Payment card details. Google Play or the App Store takes the payment; we are told only that a subscription exists.
- Your contacts, photos, files, microphone, camera, SMS or precise location. The app requests none of these permissions.
- Ads inside the app. There are none, and no ad network is given a place to show one. On Android we do read an advertising ID, for the single purpose in section 4 — crediting an ad that led to a download. That is the one exception on this list, and it is named rather than buried.
We do not sell your personal information, and we do not share it for cross-context behavioural advertising.
6. What stays on your phone
Some things never leave the device at all:
- Your session tokens — in Android's keystore-backed secure storage, or the iPhone keychain.
- The cached coin catalogue, your favourites, your Solana watchlist and recently used tokens.
- Alarm tone, volume and timeout; your theme and language choice.
- Cached coin artwork, downloaded once and reused.
Uninstalling the app removes all of this. It does not delete your account or your alerts — see section 11.
7. Permissions
The two platforms ask for different things. Neither list includes your contacts, photos, microphone, camera or location — see section 5.
Android
| Permission | What it is for |
|---|---|
| Notifications | Delivering alerts. Without it, nothing can reach you. |
| Full-screen intent, wake lock | The alarm taking over the lock screen and turning the display on. |
| Foreground service (media playback) | Keeping alarm audio playing once it has started, so Android does not kill it mid-ring. |
| Do Not Disturb access | Optional. Only if you want the alarm to get through Do Not Disturb. The app works without it. |
| Ignore battery optimisations | Optional. Stops aggressive power saving from delaying an alarm. You are asked, never forced. |
| Start on boot | Restoring a pending alarm after the phone restarts. |
| Vibrate | The alarm and notification vibration. |
| Internet, network state | Talking to our servers, and knowing when you are offline so the app can say so. |
iPhone
| Permission | What it is for |
|---|---|
| Notifications | Delivering alerts. Without it, nothing can reach you. |
| Time-sensitive notifications | Letting an alert through Focus and the scheduled summary, so a price move reaches you when it happens rather than later. |
8. Who else processes your data
These are the only third parties involved, and each one gets only what its job requires.
| Service | What it does | What it receives |
|---|---|---|
| Google Firebase Cloud Messaging | Delivers push notifications | Your push token and the notification content (the coin, the price, the alert) |
| Google Firebase Analytics | Usage analytics | Events, account id, device and app properties. No email address. No advertising identifier. |
| Google Sign-In | Optional sign-in | Only used if you choose it; returns your email address and a token to us |
| Sign in with Apple | Optional sign-in on iPhone | Only used if you choose it; returns a stable user id and either your email address or an Apple relay address |
| Google Play Billing | Takes subscription payments on Android | Handled entirely by Google under its own privacy policy |
| Apple App Store | Takes subscription payments on iPhone | Handled entirely by Apple under its own privacy policy |
| RevenueCat | Manages subscription state across stores | Your account id, which products you bought, renewal and expiry dates |
| PostHog (EU region) | Product analytics, session recording, feature flags | Events, account id, email address, session recordings (sign-in and sign-up masked) |
| Telegram | Optional alert delivery | Only if you link it: the alert text we send to your Telegram account |
| Singular | Install attribution — crediting an ad for a download | Android only. Your advertising ID, the Play install referrer, and app events such as a signup or a subscription. Nothing on iOS — the SDK is not in the iOS app. |
| Cloudflare | Serves and caches coin artwork in front of our backend | Ordinary request metadata, including your IP address |
We may also disclose data where the law requires it, or where it is necessary to investigate abuse or protect the service. We will tell you if that happens, unless we are forbidden from doing so.
9. Legal bases and international transfers
If you are in the UK, EU or EEA, we rely on these legal bases under the UK GDPR and GDPR:
- Performance of a contract — your account, your alerts, delivering notifications, running your subscription. The app cannot do its job without these.
- Legitimate interests — analytics, session recording, security logging and abuse prevention, and install attribution on Android, balanced against your privacy. You can object at any time (section 12), and Android's "Delete advertising ID" setting is a direct opt-out of the attribution half.
- Consent — the notification permission and linking Telegram. Both are opt-in and withdrawable.
- Legal obligation — keeping transaction records where tax or consumer law requires it.
PostHog data is held in the European Union. Google, Apple, RevenueCat and Singular process data in the United States and elsewhere, under the Standard Contractual Clauses and, where applicable, the EU–US Data Privacy Framework.
10. How long we keep things
- Your account, alerts and notification history — for as long as your account exists.
- Analytics events and session recordings — according to the retention set in each analytics service, after which they are deleted or aggregated. Recordings are the shortest-lived of anything we hold.
- Server logs — a short rolling window, for security and debugging.
- Billing and transaction records — as long as tax and consumer law requires, which can outlast your account. These are records of a payment, not of your activity in the app.
11. Deleting your account and data
Two routes, both of which delete the same thing:
- In the app. Settings › Privacy › Delete account. It asks you to confirm, then removes your account, your alerts and your notification history.
- By email. Write to support@appsfromzero.com with the subject Account deletion request. Include the account id shown in Settings › Privacy, or the email address on the account. We will confirm the request, act on it within 30 days, and tell you when it is done. If you never connected an account, the account id is the only way we can identify you — copy it from Settings › Privacy before you uninstall, because the app is the only place it is shown.
Deletion removes your account record, your alerts, your notification history, your linked delivery channels and your analytics person record. Billing records that we are legally obliged to keep are retained, and anonymous aggregate counts that can no longer be connected to you are not deleted because there is nothing left in them to identify.
Deleting your account does not cancel your subscription. A subscription is a contract with Google Play or the App Store, not with the app. Cancel it in the store that sold it, or from Manage subscription inside the app, before deleting your account.
Uninstalling the app clears what is on the phone, but leaves your account standing. Use one of the two routes above.
If you never connected an email, Google or Apple account, uninstalling loses your access to that account rather than deleting it. The key proving the phone owns it is stored on the phone, and on Android it is excluded from backup by design, so it does not survive a reinstall. Do not count on a backup to carry it. Delete from inside the app, or copy your account id out of Settings › Privacy first, so we can find the account and remove it for you.
12. Your rights
Depending on where you live, you have the right to access the data we hold about you, to have it corrected, to have it deleted, to restrict or object to how we use it, to receive it in a portable form, and to withdraw a consent you have given. Residents of California and other US states with comparable laws have equivalent rights, including the right not to be discriminated against for exercising them.
Email support@appsfromzero.com and we will answer within 30 days. We will not charge you, and we will not make the app worse for you because you asked. If you are in the UK or EU and we have not resolved things, you may complain to your national data protection authority.
13. Children
The app is not intended for anyone under 16, and we do not knowingly collect data from children. If you believe a child has created an account, email us and we will delete it.
14. This website
getcryptoalert.com uses Google Analytics to count visits and see which pages are read. That uses cookies and records a truncated IP address. No account is required to read this site and we set nothing else. Fonts are loaded from Google Fonts, which receives your IP address as part of that request. Browser-level opt-outs and the Google Analytics opt-out add-on both work here.
15. Changes to this policy
When this changes materially we will update the date below, and announce it in the app's release notes. The current version is always at this URL, which is the one the app links to from Settings.
16. Contact
Apps From Zero
support@appsfromzero.com
For a data or deletion request, include the account id from Settings › Privacy — it is the fastest way for us to find you, and the only way if you signed up with an address you no longer use.
Last updated: 1 November 2026 · Applies to app version 1.1.0 and later