Privacy policy

Last updated: 4 November 2026

This policy explains what Lessonberg keeps about you, why, and what you can do about it.

Who runs Lessonberg

Lessonberg is run by Oleksandr Usenko, an individual based in Spain, who decides how your data is used (the “controller” in data-protection law). Write to lessonberg@gmail.com about anything in this policy.

What we keep

• Your account: your email address, your first and last name, your language settings, the time zone of the browser you last used (so emails show due dates and lesson times in your own time) and, if you set one, your password, stored only as a scrambled hash that can't be read back.
• Your phone number and picture, if you add them: the tutors of the courses you've joined, and the students who have joined your courses, see them; nobody else does. Removing a student from a course, or deleting the course, hides them again. Your picture is stored with the rest of your data, in Frankfurt, and removing it in Settings deletes it from our servers.
• Your themes, if you pick them: up to 5 interests from our list, such as football or a book series, so your tutors can write your homework about them, and whether you've said you don't want to pick any. The tutors of the courses you've joined see them; nobody else does. Removing a student from a course, or deleting the course, hides them again. You can change or remove them in Settings.
• If you sign in with Google: only your email address, your first and last name and whether Google has verified the email, plus the Google account ID that links the two. We also receive an access token, which is stored encrypted and never used. We don't keep your Google profile picture or the ID token Google sends.
• Teaching: the courses you create, the name you show your students, the email addresses of the students you invite, each student's level and your note about them, and the homework you generate, edit and assign. When you start teaching, we get an email with that name and your email address, so we know who is teaching; it reaches a Gmail mailbox through Mailgun.
• Your plan, if you teach: which plan you're on and its status, a custom plan's limits, and how many generations each homework used, to apply your plan's limits.
• Learning: the courses you've joined, your answers to their homework, saved as you type, and how each answer was checked (right, almost or wrong, in how many tries, and the feedback on it), which your tutor sees. Your tutors see your name and email address; if you change your email, they see the new one. A checked translation's, rewritten sentence's or built sentence's text and verdict are also kept with the homework, without your name, so the same answer isn't checked twice.
• Lessons: when a lesson is and how long, who it's for, whether it's online or in person, what the tutor writes about it, and the links they add to the meeting and its recording. Its tutor and its students see them: the meeting link until the lesson ends, the recording link after. A student who joined a course after a lesson ended doesn't get the link to its recording. A recording stays wherever the tutor keeps it, such as Zoom or Google Drive: we keep only the link, and who can open it is set there.
• Signed-in sessions: for each device you're signed in on, its IP address and browser, and when the session ends.
• Generation and checking records: when each part of a homework was generated or an answer was checked, and what it cost, for accounting and the plan's limits.
• Searches of our theme list that find nothing: the words searched, the interface language and whether a student or a tutor searched, counted, with when the same words were first and last searched, so we can see which themes the list lacks. We don't record who searched.
• Grammar topics that couldn't be used: the words typed as a homework's grammar topic, the course's language and why they couldn't be used, counted, with the day the same words were first and last refused, so we can improve the check. We don't record who typed them.

Apart from counting those searches and refused topics, we don't use analytics, we don't use advertising, and we don't sell or rent your data.

Why we keep it

• To provide the service you signed up for (GDPR Article 6(1)(b)): your account, your plan, courses, invitations, lessons, homework and answers.
• For security, which is a legitimate interest (GDPR Article 6(1)(f)): sessions, IP addresses and limits on repeated attempts protect accounts from abuse, and the email telling us who starts teaching lets us spot misuse early.

Who processes it for us

• Fly.io hosts the app, in Frankfurt, Germany.
• Neon hosts the database, in Frankfurt, Germany.
• Mailgun sends our emails, from its EU region.
• Anthropic writes the exercises and checks students' translations, rewritten sentences and built sentences. A request to write exercises carries the language, level, theme, grammar topic and any words you listed, of a course or of one student's homework (a theme from our list by its English name, a theme or words you typed as you typed them, and the grammar topic as our check named it), and, when you regenerate one exercise, the section's other exercises and its instructions; a request to check a translation, a rewritten sentence or a built sentence whose order the exercise doesn't list carries the exercise, the course's languages, the level and the student's answer as they typed it or put it together. When you press Generate, the grammar topic and any theme or words you typed are also sent on their own, to check that the topic is grammar and the theme and words suit everyone; each answer is remembered as a keyed fingerprint, without the text, and a refused topic's answer, or a theme's or a word's, is remembered only for you. Neither carries anyone's account name or email address, or your notes about students: only what's typed into the homework itself. Anthropic processes these requests in the United States under its data processing addendum, which includes the European Commission's standard contractual clauses, and doesn't train its models on them.
• Google signs you in if you choose it, as a separate controller under its own privacy policy. It also runs the Gmail mailboxes we read email in, which hold what you write to us and the emails telling us of new tutors. They're personal accounts, which Google may store outside the EU, under its own terms and with no data processing agreement.
• Pwned Passwords (Have I Been Pwned) checks new passwords against known data breaches. It receives only the first 5 characters of a scrambled version (hash) of the password, which identify neither you nor the password.

Google user data

Lessonberg uses the information it receives from Google (your email address, your first and last name and whether the email is verified) only to sign you in and to show your name in the app. It isn't sold, shared with anyone else or used for advertising. Lessonberg's use and transfer of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.

Cookies and storage

Lessonberg sets one cookie, which keeps you signed in. If you sign in with Google, it also sets a short-lived cookie (a few minutes) that keeps that sign-in attempt safe. Both are strictly necessary. Your browser also remembers the interface language you chose. There are no analytics, advertising or tracking cookies.

How long we keep it

• Your account, your plan, courses, lessons, homework and answers: until you ask us to delete your account. Deleting a course or a homework in the app, or removing a student, hides it; it's erased for good with your account.
• The email telling us you started teaching: deleted from our mailbox within 3 months.
• Signed-in sessions: 30 days, or until you sign out or sign in again in that browser.
• Sign-in, confirmation, set-password and email-change links: they expire after 15 to 60 minutes.
• Checked translations, rewritten sentences and built sentences kept without a name: as long as the homework they belong to.
• Theme searches that found nothing: a year after anyone last searched for the same words.
• Grammar topics that couldn't be used: a year after anyone last typed the same words.
• Checks of grammar topics, themes and words, kept without the text: until we change how we check them, and at most a year.
• Generation and checking records: as long as accounting needs them.

Your rights

You can change your name, phone number, picture, themes and email address yourself in Settings. Changing your email takes two emails: one to your current address to approve the change, then one to the new address to confirm it.

You can also ask to see, correct, export or delete your data, or object to or restrict how we use it, by writing to lessonberg@gmail.com. There's no “Delete account” button yet: write to us and we'll delete it. If you think we've handled your data wrongly, you can complain to Spain's data-protection authority, the Agencia Española de Protección de Datos (AEPD).

Children

In Spain, people can agree to how their data is used from the age of 14. Younger students use Lessonberg through their tutor, with a parent's or guardian's consent.

Changes

When this policy changes, we'll update this page and its date. If a change affects how your data is used, we'll also tell you by email.