Last updated: 24 October 2026
Plainletter explains the paper mail you scan. Letters are personal, so the app is built to send as little as possible, keep nothing on our side, and leave your letters on your device.
Only when you scan or choose a letter, and only after you agree on first launch, Plainletter sends: the photos of that letter's pages (up to four, reduced in size), today's date, and your preferred language. Nothing is sent in the background.
The photos go to our server, hosted by Vercel, which passes them to Anthropic's Claude AI to read the letter and write the explanation, then returns that explanation to the app. Our server does not store the photos or the explanation, and does not log their content; its logs record only technical details such as request size, timing and errors. Like any web service, Vercel records standard request information such as IP addresses for security and operations.
Anthropic processes the photos under its commercial terms. It does not use them to train its models, and keeps API data only for a limited period for safety and abuse monitoring. See Anthropic's Privacy Policy and Privacy Center.
Each explanation is saved on your device so you can come back to it. The photos themselves are not saved. You can delete any letter in the app by swiping it away; deleting the app removes all of them. We cannot see or recover them.
If you tap Remind me on a deadline, Plainletter asks for access to Reminders and adds that one reminder on your device. It does not read your other reminders.
No accounts, no advertising, no analytics or tracking, no selling or sharing of data. The app contains no third-party SDKs.
Plainletter is not directed at children under 13 and does not knowingly collect their data.
If this policy changes, the new version will be posted here with a new date.
Questions? Email support@onyxtech.info · ONYX Tech LLC.