Privacy Policy
This policy explains what personal data Letros collects, why, and what rights you have. TOTORO TEACHER DOO BAR is the controller for teacher and administrator accounts. For student data entered by a school, the school is the controller and we process it on the school's behalf.
What we collect
- Account data: name, email, username, role, school and language.
- Teaching content: courses, lessons, homework, answers, comments, uploaded files, and essays you check (photos and text).
- Usage data: pages opened and buttons used, approximate country and city derived from the IP address, browser type. We store a salted hash of the IP address, not the address itself.
- Payment data: handled by Paddle. We receive the plan, status and renewal date, never your card details.
Why we use it
- To provide the service: sign-in, lessons, homework and the writing checker (contract).
- To keep the service secure and prevent abuse, for example sign-in limits (legitimate interest).
- To understand which features are used and improve them (legitimate interest). We do not sell data or use it for advertising.
Where it is stored
Our servers, database, uploaded files and backups are hosted by Hostinger in Germany (EU).
What the AI services receive
We send an AI service only what the feature needs, never account data such as names, email addresses or usernames, and never student answers or grades.
- Anthropic (Claude): the essay photos and text you check with the writing checker; the textbook photos, PDF and Word files and requests you use for "Make with AI" and import from a photo; and words added to a dictionary, to translate them. Whatever is written on an uploaded page (for example a student's name on an essay) is part of the photo. Anthropic does not use this data to train its models.
- OpenRouter: lesson titles and dictionary words, to draw lesson covers and word pictures.
- OpenAI: the text of exercises and vocabulary, to read it aloud.
Covers and audio are made automatically from lesson titles and exercise text, so do not put personal data there. The other AI features run only when you use them. These services are in the United States.
Other services that process data for us
- Resend: sends sign-in codes by email.
- Paddle: payments, invoices and taxes, as Merchant of Record.
- Hostinger: hosting of our servers and database.
Where a provider is outside the EU, transfers rely on the European Commission's standard contractual clauses or equivalent safeguards.
Cookies
We use only first-party cookies needed for the service: your session (up to 90 days), your interface language, and an anonymous visitor id for our own usage statistics. No advertising or third-party tracking cookies.
How long we keep it
We keep account data and content while the account exists. Photos of essays checked with the writing checker are kept for 7 days to troubleshoot text recognition, then deleted. When an account is deleted, its data is removed within 30 days, except records we must keep by law (for example payment records kept by Paddle).
Your rights
You can ask to see, correct, export or delete your data, and object to its use, by writing to hello@letros.app. Students should contact their school first. You can also complain to your data protection authority.
Last updated: 22 October 2026. Contact: hello@letros.app. Letros is operated by TOTORO TEACHER DOO BAR, Topolica III, Bar, Montenegro.
Data location: Germany (EU). Schools: Data Processing Agreement · Sub-processors.