Numo
Privacy Policy
In short: your regular conversions, calculations and saved currency lists stay on your device. If you enable rate alerts, the alert details and push token are sent to Numo's alert service. Numo requires no account, downloads exchange rates, uses Google Firebase for pseudonymous usage analytics and crash diagnostics, and shows no ads.
This policy explains what information the Numo app ("Numo", "the app"; previously named Converter) handles, why, and the choices you have. Numo is developed and published by Vladimir Pavlov, an individual developer ("I", "me"), who is the controller of the personal data described here.
1. Data that stays on your device
The following core converter data stays on your iPhone. It is not uploaded as part of ordinary conversions; details that you separately choose for a rate alert are handled as explained in section 3:
- amounts entered into the converter and calculator expressions;
- saved converter currency lists, favorite currency, and their order;
- your rate adjustment, appearance, and other settings;
- cached exchange rates;
- widget configuration. Widgets read cached rates from storage shared only between the app and its own widgets on your device;
- custom rates and custom assets you create, including any image you choose for an asset;
- whatever the price scanner sees. Camera frames, photos and documents you scan are read on your iPhone with Apple's on-device text recognition and are never uploaded or stored by Numo.
Deleting the app removes this on-device data. It does not automatically delete rate alerts stored by the alerts service; see section 3 for how to remove those.
2. Exchange rates
To show current rates and rate history, the app requests them from Frankfurter (api.frankfurter.dev), with ExchangeRate-API (open.er-api.com) as a backup. Cryptocurrency prices come from Numo's own service (numo.vpavlov.com), which relays prices provided by CoinMarketCap. These requests contain only currency codes and dates, never the amount you enter or any identifier. Like any web server, these services receive your device's IP address and standard technical request information in order to respond. Their handling of that information is governed by their own policies.
3. Rate alerts (when available and enabled)
Price alerts are optional and need an online service to check exchange rates and deliver notifications while Numo is closed. When you first open price alerts, Numo registers this app installation with the service: it sends a random installation identifier and an Apple App Attest attestation, which proves that requests come from a genuine copy of Numo on an Apple device; the service keeps only the public key from it, to check that later requests come from the same installation. When you create or change an alert, Numo sends the base and target currencies, the amount you choose for the alert, the above/below condition, and the threshold you set to Numo's alerts service. These alert rules are stored on the service so they can be checked until triggered, paused or deleted.
If you allow push notifications, the service also receives this iPhone's Apple Push Notification service (APNs) token and its push environment to deliver notifications through Apple. The token is used for alert delivery, not for advertising. Apple and the service's infrastructure provider process the technical information needed to route those notifications. Network requests can expose standard technical data such as an IP address to the hosting infrastructure; the alert database does not store an IP address or device name.
To check whether you can use Free or Pro alert limits, the app may send Apple-signed StoreKit transaction information to the alerts service. The service verifies the purchase and keeps the entitlement tier, expiration date, verification time and the purchase's original transaction identifier, so that Apple's App Store Server Notifications about renewals, refunds and revocations can update your alert limit. Your payment card details, name, email and Apple Account credentials are not sent to the alert service.
The alerts service associates this information with a random installation identifier, not a Numo user account. In the app, choose Delete all alert data to remove the saved alerts, push token and installation record from Numo's service. Deleting or uninstalling the app alone does not guarantee deletion of server-side alert data. When this feature is unavailable in a release build, Numo does not register alert rules or push tokens with the service.
4. Usage analytics and crash reports
Release versions of the app use Google Firebase Analytics and Crashlytics, provided by Google LLC, to understand which features are used and to fix crashes.
What is sent
- Product interaction: events such as opening the app, completing a conversion, using the calculator, adding or removing a currency, opening the app from a widget or control, rate refresh success or failure, and steps of a Numo Pro purchase, including which plan (monthly, annual, or lifetime) was chosen.
- Crash and diagnostic data: crash stack traces, the device state at the time of a crash, and categorized error types for failed rate refreshes or purchases.
- Technical context: app version and build, device model and family, operating system version, and an app-instance identifier generated by Firebase. Google may derive an approximate country or region from the IP address of the request.
What is not sent to Firebase
Converter amounts, alert amounts and thresholds, calculator expressions, selected currency codes, widget settings, your name, email address and Apple Account identifiers are not sent to Firebase. The app does not set a user ID in Firebase.
Limits
Analytics advertising features are turned off: ad storage, ad user data, and ad personalization are denied, and the app does not use Apple's advertising identifier (IDFA) for analytics. Analytics event data is kept for up to 2 months; crash reports are kept for up to 90 days.
See Privacy and Security in Firebase for how Google processes this data.
5. No advertising
Numo contains no ads and no advertising software. It does not show ads, does not share data with ad networks, and does not use Apple's advertising identifier (IDFA).
6. Purchases
Numo Pro is available as a monthly or annual subscription or as a one-time lifetime purchase. Payments, renewals, cancellations and refunds are processed by Apple. I do not receive your name, payment-card details or Apple Account credentials. The app uses StoreKit to check access locally. If you use server-backed rate alerts, Apple-signed transaction information may also be sent to Numo's alerts service to verify your Free or Pro alert limit, as explained in section 3.
7. Tracking
Numo does not track you as defined by Apple: it does not link data collected in the app with data from other companies' apps or websites for targeted advertising or measurement, and it does not share data with data brokers.
8. Sharing and transfers
I do not sell your personal data. Information is processed by the service providers needed for the features you use: Google for Firebase, your selected exchange-rate provider, and, if you enable rate alerts, the hosting infrastructure for Numo's alerts service and Apple for push delivery. Information may also be disclosed when required by law. These providers may process data in the United States and other countries, subject to applicable data-transfer safeguards.
9. Legal bases (EEA, UK, and Switzerland)
| Purpose | Legal basis |
|---|---|
| Downloading exchange rates | Performance of the service you request |
| Storing, checking and delivering rate alerts, and verifying alert limits | Performance of the service you request |
| Crash reports and error diagnostics | Legitimate interest in keeping the app reliable |
| Usage analytics | Legitimate interest in understanding and improving the app, using pseudonymous data with advertising features disabled |
10. Your rights
Depending on where you live, including under the GDPR, the UK GDPR, and California law (CCPA/CPRA), you may have the right to access, correct, or delete personal data about you, to object to or restrict its processing, to data portability, to withdraw consent, and to lodge a complaint with your local data protection authority. California residents also have the right to know what personal information is collected and to opt out of its sale or sharing. Numo does not sell personal information or share it for cross-context behavioral advertising.
Numo has no user accounts. If you use rate alerts, the service stores rules under a random installation identifier; the app's Delete all alert data action removes that installation's server records. For other requests, email me with enough detail to identify the data you mean; without an account, I may not be able to locate records by name or email alone. I will respond within 30 days. Deleting and reinstalling the app generates a new Firebase app-instance identifier, but does not automatically delete previously stored server alert rules.
11. Children
Numo is a general-audience utility and is not directed to children under 13 (or the minimum age in your country). I do not knowingly collect personal data from children. If you believe a child has provided personal data, contact me and I will delete it.
12. Security
All network requests made by the app use encrypted HTTPS connections. Data on your device is protected by iOS security features.
13. Changes
If this policy changes, I will update this page and its effective date. Significant changes will also be noted in the app's release notes.
14. Contact
Vladimir Pavlov
vpavlov.me@gmail.com