LetterSprig

Privacy Policy

October 6, 2026

LetterSprig is made by Rômulo Carvalho, an independent developer in Brazil ("we"). This policy explains what the app and our server handle, why, and for how long. We wrote it to match exactly what the app does.

The short version

You can use LetterSprig without an account. We do not show ads, we do not sell data and we do not track you across apps or websites. Your practice history stays on your device; the app only sends us anonymous usage statistics, which you can turn off. A photo of your page leaves your device only when you ask for a letter check, and we delete it from our server within 24 hours.

What stays on your device

Your chosen languages, lessons, progress, review schedule, reminders and any photos you decide to keep are stored only on your iPhone or iPad. Deleting the app deletes them. You can also erase them in Settings › Privacy › Delete all my data.

Anonymous app identifier

To keep your purchases and letter check credits working, the app creates a random identifier and a secret key and stores them in your device's Keychain. They are not linked to your name, email or phone number. Our server stores the identifier and a hash of the secret, never the secret itself.

Usage statistics

To understand where the app helps and where people get stuck, the app sends our server short usage events, such as "finished the introduction", "started a lesson", "opened the plans screen" or "an error screen appeared", together with the app version, the app language and your device's region setting. Our server also notes on which days the app contacted it, to count how many people come back. These records are linked only to the random app identifier, never to your name or Apple ID, and never include your photos, what you wrote or your results. We use them only to improve LetterSprig, never for advertising, and no third party receives them. We keep them for up to 13 months. You can turn this off at any time in Settings › Privacy › Share usage statistics.

Purchases

Payments are handled by Apple. We never see your card or Apple ID. When you buy LetterSprig Plus or a letter check pack, the app sends us Apple's signed transaction so our server can confirm it. We keep the transaction and product identifiers, dates, and whether a subscription is active, trial or refunded, to give you access and credits. We keep these records while your app identifier exists and as required by tax and accounting law.

Letter check on a photo (optional, beta)

Before the first analysis, the app asks for your permission and explains who processes the photo. If you allow it, the app sends the cropped photo you confirmed, together with the letters you practiced, the script and the language of the explanation, to our server. Our server sends them to OpenRouter, Inc. (United States), which routes the request to the AI provider named on the permission screen. We request routes that do not store or train on your data where the provider offers that option.

The photo is used only to produce your letter check. We delete it from our server as soon as the analysis ends, and in any case within 24 hours. We keep the written result so you can read it again, until you delete it or delete your data. You can withdraw permission at any time in Settings › Privacy; this stops future uploads but cannot undo an analysis that has already been completed.

Please do not photograph documents with personal information. The app asks you to crop the photo to your practice before sending.

Server logs

Our server keeps technical logs (time, route, response code, duration and a hashed network address) for up to 30 days to keep the service secure and working. Logs never contain photos, what you wrote or your secret key.

What we do not do

No advertising, no advertising identifiers, no third-party analytics, no data brokers, no sale or sharing of personal data for marketing, no face recognition, no handwriting analysis of personality or health.

Your rights and choices

In Settings › Privacy you can export the data our server keeps about your app identifier, delete your photos, withdraw AI permission and delete all your data. Deleting your data removes your identifier, credits, feedback and photos from our server; it does not cancel an App Store subscription, which you manage in your Apple account settings.

Depending on where you live (for example under the GDPR, the UK GDPR, the Brazilian LGPD or US state laws) you may have rights to access, correct, delete or port your data and to object to processing. Contact us at the address below; we answer within 30 days.

Legal bases

We process data to provide the app you asked for (contract), with your consent for the AI letter check, for our legitimate interest in keeping the service secure, and for our legitimate interest in understanding how the app is used so we can improve it (you can object by turning off usage statistics). Purchase records are also kept to meet legal obligations.

International transfers

Our server runs in a data center operated by our hosting provider. OpenRouter and AI providers may process requests in the United States or other countries. Where required, transfers rely on the providers' standard contractual safeguards.

Children

LetterSprig is designed for adults and teenagers learning or improving handwriting. It is not directed to children under 13, and we do not knowingly collect data from them.

Changes and contact

If we change this policy we will update this page and the date above, and tell you in the app before any change that affects how photos are processed. Questions or requests: romulorgc@gmail.com.