Privacy Policy

Effective and last updated: November 13, 2026

1. Who we are

Letter Sense (the "App") is an iPhone app run by an independent developer in the United States ("we", "us"). For privacy questions or requests, write to privacy@lettersense.app. For help with the App, write to support@lettersense.app.

2. In short

You photograph a paper letter, an SMS or an email screenshot. The App sends the photo to our server, and our server sends it to an artificial intelligence (AI) service run by Anthropic in the United States, which reads it. You get a "card" that explains the letter in your language.
Photos of your letters are stored on our server in encrypted form until you delete them. You can delete one letter, or your whole account, inside the App.
If you add trusted people, they receive emails with short summaries (cards only, never photos).
We do not sell your data, show advertising, or track you across other companies' apps and websites. The App has no advertising or analytics code.
Under Anthropic's commercial terms, Anthropic may not train its models on the content we send. We do not use your letters to train AI models either.
The App explains letters. It is not a lawyer, tax adviser, doctor or insurance adjuster. See the Terms of Use.

3. Information we collect

Account

An identifier that Apple gives us when you use Sign in with Apple; your name if Apple shares it (we ask for the name only, not your email address); the display name and language you choose; the time the account was created; and sign-in tokens (stored only as a one-way hash).

Letter photos

The images you take or choose, including every page of a letter. The App reduces the photo size and saves it as a JPEG before sending it. We do not ask for your location.

Letter cards

The text produced from the photo: a short title, the sender and type of letter, a deadline, an amount, short quotes from the letter, suggested general steps, a "possible scam" label, a "specialist needed" flag, how sure the reading is, the folder, and words used for search. Also your actions: marked as done, hidden from trusted people, a deadline you corrected, a folder you chose. Cards may contain sensitive information printed in your letter, for example health, financial or tax details.

Trusted people

For each person you add (up to three): email address, optional name, the language of the emails, whether they confirmed, and a secret link code. Add only people who agree to receive these emails.

Consent record

Which version of the AI-processing consent you accepted, and when.

Subscription

Purchases are handled by Apple. We do not receive your payment card details. To unlock features, the App sends us Apple-signed purchase data. We verify the signature and store the product, dates, status and Apple transaction identifiers for your account.

Technical and security records

Server records of requests (time, IP address, error type, letter identifier) that are rotated automatically and kept only for a short time. A security log of sign-ins, consent, account deletion and subscription events, with IP addresses, is kept for 90 days. We also keep counters of how many letters you have added in total and per day, to apply the free-letter limit and the daily limit. We do not write the content of your letters into logs.

Stored on your phone

Your language choice, a counter of the letters you added (used for the free-letter limit), the sign-in token (in the iOS Keychain), and reminders that the App schedules as local notifications.

Permissions the App asks for

Camera, to photograph your letters. Notifications, to show reminders; if you say no, the App still works, without reminders. When you choose existing photos, the App uses the system photo picker and receives only the photos you pick, never your whole library.

We do not collect your contacts, your location, advertising identifiers or browsing history, and we do not collect data for analytics or advertising.

4. How we use information

To read your letters and show you cards.
To schedule reminders on your phone and to send emails to trusted people you added.
To keep your account secure, prevent abuse (for example a daily limit on letters), fix errors, and comply with the law.
To manage your subscription status and answer your requests.

We do not use your letters for advertising, profiling or sale, and we do not use them to train AI models.

5. AI processing (Anthropic)

To read a letter, our server sends the page images, our fixed instructions, today's date and the card language to the Claude API provided by Anthropic PBC in the United States. The images are resized before sending. If the first reading is uncertain, we may send the same images a second time. We do not send your name, email address or account identifier with the images. Anthropic returns the card text to us.

Anthropic acts as our service provider. Its published policies for API customers say that inputs and outputs are deleted automatically within 30 days, with limited exceptions (for example where the law requires longer retention or to enforce its usage policy), and that content sent through the API is not used to train its models by default. Anthropic's own terms and policies apply to its handling of data:

AI output can be wrong or incomplete. Always check dates and amounts against the paper original. You asked us to process your letters with AI when you accepted the consent screen in the App.

6. Who we share information with

Anthropic PBC (United States): letter page images (section 5), to read the letter.
Linode, an Akamai company (United States, Miami, Florida): hosts our server, so all data stored on the server, in encrypted or ordinary form as described here, is on its infrastructure.
Resend (United States): sends our emails, so it handles trusted people's email addresses and the text of messages sent to them.
Apple: Sign in with Apple, App Store purchases and subscription management, and TestFlight during testing. Apple's own privacy policy applies.
Trusted people you add: card titles, deadlines, amounts and warning notes (section 8). Never photos.
Authorities, courts and advisers: only what the law requires, or what is needed to protect rights, safety or the service.
A buyer or successor: if the business is sold or transferred, your data may transfer under this policy.

We do not sell personal information and do not share it for cross-context behavioral advertising.

7. Sensitive content

Letters may contain health, insurance, tax, immigration, court or financial details, and may name other people. Upload only letters addressed to you, or addressed to someone who has allowed you to upload them. We do not look for these categories on purpose, and we use them for no purpose other than reading the letter for you.

8. Trusted people

With Letter Sense Plus you can add up to three trusted people by email address. We send each person an invitation. They receive nothing else until they confirm by link. After they confirm, they receive:

a weekly summary: letters from the week that need action, overdue items not marked done, and a count of letters;
an urgent alert when a new letter has a deadline within 7 days, falls into a "specialist needed" category (for example court, tax penalty, immigration, insurance claim, collections), or shows signs of a scam.

These messages include the card title, deadline, amount and warning notes, and the name you set in the App. They never include photos. A letter you mark as hidden is left out of summaries and alerts. Every email has a link to unsubscribe, which removes that person from our list. You can also remove a person in the App. Trusted people do not get an account and do not gain any legal authority; the App does not replace a power of attorney.

9. How long we keep information

Letter photos and cards: until you delete the letter or your account. We do not currently delete them automatically.
Account data, consent record, sign-in tokens, purchase records: while your account exists; deleted with the account.
Trusted person records: until you remove the person, they unsubscribe, or your account is deleted.
Security log: 90 days. When you delete your account, your entries are removed and one anonymous record of the deletion remains.
Server request logs: rotated automatically and kept only for a short time.
Backups: we keep nightly backups of the database and of the encrypted photos for 14 days, and the hosting provider keeps disk backups. Data you delete disappears from backups within 30 days. The key that decrypts photos is not stored in the backups.
Email delivery records: kept by our email provider under its own policy.
Data held by Anthropic: according to Anthropic's policies (section 5).
Legal and safety: longer if the law requires, or to resolve a dispute or investigate abuse.

10. Deleting your data

One letter: open the letter and tap the delete button, or swipe the letter in the list. The photos and the card are removed.
Everything: Settings, then Privacy, then "Delete all my data". This removes your letters, photos, cards, trusted people, consent record and account from our server. It cannot be undone. When you do this we also ask Apple to revoke the App's Sign in with Apple connection.
A trusted person: Settings, then Trusted persons, then swipe to delete; or use the unsubscribe link in any email.

Deleting your account does not cancel your subscription. Cancel it in your Apple ID subscription settings. Deleting the App from your phone does not delete data on our server. Data already sent to Anthropic is handled under section 5. If you cannot delete something in the App, email privacy@lettersense.app.

What remains after deletion. Nothing that identifies you stays in our database except one anonymous record that an account was deleted. Copies in our backups disappear when the backups expire (section 9). Data already sent to Anthropic follows Anthropic's policies, emails already sent to trusted people stay in their mailboxes, and Apple keeps its own records of your purchases and of Sign in with Apple.

11. Your choices and rights

You can view your cards in the App; edit your display name, language, deadlines and folders; hide letters from trusted people; unsubscribe trusted people; and delete data as described above. You can decline the AI-processing consent, but then the App cannot read letters. To withdraw consent later, delete your letters or your account, or contact us. To ask for a copy of your data, a correction, or a deletion you cannot do in the App, write to privacy@lettersense.app. We aim to respond within 30 days.

12. Security

Photos are stored encrypted on our server with a key kept separately from the database. Connections between the App and our server use HTTPS. The server's disk is encrypted by the hosting provider, and access to the server is limited to us by key-based login. Access to letters is limited to your account, and we do not create public links to letters. Card text and account records are kept in our database. No system is completely secure. If a breach affects your information, we will notify you as the law requires.

13. Children

The App is for adults (18 and older). It is not directed to children, and we do not knowingly collect information from children under 13. If you believe a child has used the App, contact us and we will delete the account.

14. Where information is processed

Our server, our email provider and Anthropic are in the United States. The App is intended for people in the United States.

15. This website

This website, lettersense.app, is static. It has no accounts, sets no cookies, and has no analytics or advertising trackers. Like any web server, ours may keep standard technical logs (IP address, page requested, time) to run and secure the site; they are rotated automatically.

16. Changes to this policy

If we make material changes, we will update the date above and tell you in the App or by email before the changes take effect. If a change affects how we share your letters with AI providers, we will ask for your consent again. If we provide this policy in other languages and they differ, the English version prevails.

17. Contact

Privacy: privacy@lettersense.app
Support: support@lettersense.app
Web: lettersense.app/support