Privacy policy
Pennyweight Jewelry Identifier (the "app") and the website pennyweight.joseluissaorin.com (the "site")
Last updated: 11 November 2026
Who we are
The app and the site are published by José Luis Saorín Ferrer, an individual developer (NIF 79081262V), Calle Prolongación Ramón y Cajal, 1C, 3B, 38003 Santa Cruz de Tenerife, Spain, who is the data controller. Contact: pennyweight@joseluissaorin.com.
The short version
- The app has no accounts. We never ask for your name, email address or phone number.
- The photos you take of a piece are sent to our server and on to Google Gemini so that it can describe them. Our server does not store them. Google keeps them for a limited period to detect abuse.
- The weight you type in and your saved pieces stay on your phone.
- We collect basic usage events tied to a random identifier, not to your name.
- Purchases are handled by Apple and RevenueCat. We never see your payment details.
- The website has no cookies, no analytics and loads nothing from other sites.
The app: what leaves your phone
Photos of your piece
The app uses the camera, and only the camera: it does not ask for access to your photo library. When you ask the app to analyse a piece, and only after you have given permission in the app, the photos you took for that analysis are sent over an encrypted connection to our server (hosted on Cloudflare) and passed on to Google's Gemini API, which returns a description of what is visible: marks, materials as stamped, construction and style. The same applies to the sample pieces the app offers, when you choose to read one.
- Our server handles each photo in memory only while your request is in progress. It does not save photos or results, and it does not store your IP address.
- Google processes the photos to produce the description. Google logs requests and responses for a limited period (55 days according to its published policy) to detect and prevent abuse; during that time authorised Google staff may review them for that purpose. We use the paid Gemini API. Under its terms for paid services (https://ai.google.dev/gemini-api/terms) Google acts as our processor and does not use your photos or the results to improve its products or train its models.
- Only the photos you take in the app for an analysis are sent.
Please do not photograph people, documents or anything else personal alongside the piece.
App verification
To make sure requests come from a genuine copy of the app, your phone creates a cryptographic key through Apple's App Attest service. Our server stores an identifier for that key, its public part and a usage counter. This identifies an installation of the app, not you as a person.
Usage analytics
We run our own analytics service on Cloudflare. No third-party analytics company is involved. For each event (for example "photo taken", "result viewed" or "purchase screen opened") we store:
- a random identifier created by the app on your phone, and a session identifier,
- the event name and time, and the name of the screen,
- the app version, the platform, the device model, the language set on your phone and whether the app runs on a device or a simulator,
- your country, derived from your IP address at the moment of the request (we do not store the IP address),
- for a few events, one extra detail: how long a step took, how many pieces you have saved (a number only), which kind of scale you selected, which channel you shared through, or, for purchase events, the price and currency of the plan you looked at or bought.
Events never contain your photos, the weight you entered, or the contents of your saved pieces. When the purchase service is active, we also link the random analytics identifier to the random user identifier that RevenueCat assigns, so that we can see which events lead to a purchase. Neither identifier is your name.
Purchases
Subscriptions and purchases are processed by Apple. We use RevenueCat to know whether a purchase is active. RevenueCat receives a random app user identifier, your purchase history for this app, and technical data such as country and app version. We do not receive your name, Apple ID or payment card.
Metal prices
To show metal prices the app downloads a public price list from api.gold-api.com, a third-party service. The request asks only for the price of gold, silver, platinum and palladium. It carries no information about you or your piece, but like any internet request it shows your IP address to that service.
The app: what stays on your phone
- The weight you type in and the scale you select.
- Your saved pieces, including their photos and results.
- The melt value calculation, which is done on the device.
Deleting the app deletes this data.
The website
The site has no accounts, no cookies, no local storage and no analytics, and it loads no fonts, scripts, images or frames from other sites. The calculator and the stamp search run in your browser: the weights, stamps and prices you type are not transmitted to us. We do not observe any measurement tool active in the pages as served. The pages are served by Cloudflare Pages, which, like any web host, handles your IP address and technical request data to deliver the pages and defend against attacks (see https://www.cloudflare.com/privacypolicy/). When you follow a link to another site, such as a price source or the App Store, that site's own policy applies. If you write to us, we use your message only to answer it.
Why we use this data, and our legal basis
Where the GDPR or the UK GDPR applies:
| Purpose | Data | Legal basis |
|---|---|---|
| Describing the piece you photograph | Photos, results | Performance of the service you request (Art. 6(1)(b)). We ask your permission in the app before the first photo is sent |
| Preventing abuse of the service | App verification key | Legitimate interests (Art. 6(1)(f)) |
| Understanding how the app is used and fixing problems | Usage events | Legitimate interests (Art. 6(1)(f)); you may object, see below |
| Providing what you bought | Purchase status | Performance of a contract (Art. 6(1)(b)) |
| Showing metal prices | Your IP address, seen by the price service | Legitimate interests (Art. 6(1)(f)) |
| Answering your messages | Your email address and message | Legitimate interests (Art. 6(1)(f)) |
We do not sell personal data. We do not use your data for advertising or share it with data brokers. The app contains no advertising or tracking software.
Who processes data for us
- Cloudflare, Inc.: hosting of our server, analytics database and website.
- Google (Gemini API): analysis of photos.
- RevenueCat, Inc.: purchase status.
- Apple: payments and app verification.
- api.gold-api.com: metal prices (receives the request described above).
These companies may process data outside the European Economic Area and the United Kingdom, including in the United States. Where they do, transfers rely on the safeguards in their data processing terms, such as the European Commission's standard contractual clauses and the UK addendum.
How long we keep it
- Photos and results: not kept on our server. Google: a limited period, as described above.
- App verification key: we do not delete it automatically today. We keep it while the app is in use and delete it when you ask or when we close the service.
- Usage events: same as above. They are tied to a random identifier, not to your name; we do not delete them automatically today and will remove those we no longer need.
- Purchase records: as long as required to provide your purchase and to meet tax and accounting obligations.
- Emails you send us: until your request is answered and for as long as needed to keep a record of it.
Your rights
Depending on where you live, you may have the right to access, correct, delete, restrict or object to the processing of your data, and to data portability.
You decide whether photos are sent: the app asks before the first one, and if you tap "Not now" nothing is sent and the app asks again the next time you want to analyse a piece. The app does not yet have a switch to withdraw that permission later; to withdraw it, simply stop using photo analysis, or delete the app. You may also write to us.
To ask for access to or deletion of your data, email pennyweight@joseluissaorin.com. Because the app has no accounts, we cannot find data about you on our own: photos are not kept on our server, and usage events and the app verification key are tied to random identifiers that we cannot link to a person. The app does not currently show those identifiers, so we can act on those records only if you can give us the identifier; we will tell you honestly what we can and cannot find. Purchase records are held by Apple and RevenueCat, and you can ask them directly. We reply within one month.
You also have the right to complain to a data protection authority: in Spain, the Agencia Española de Protección de Datos (aepd.es); in the United Kingdom, the Information Commissioner's Office (ico.org.uk).
Children
The app and the site are not intended for anyone under 18.
Changes
If we change this policy we will update the date above and, for significant changes, tell you in the app.