Privacy

We store the minimum needed to run the app: your email (sign-in), the name you give your samurai, the cards and decks you use, your study history, and your streak. We do not sell or share this data.

When you sign in with Google, we receive your email and profile photo from Google. When you sign in with email magic link, we send a one-time link via Resend.

Card audio and card illustrations are generated and stored by our service providers. Only the word being spoken or illustrated is sent — never your name, email or account id — and each result is reused by every learner of that word, so it never identifies you.

Some optional features send text to an AI provider: example-sentence suggestions send the word and its translation, the conversational practice exercises send the text you type in that exercise so it can be answered or corrected, and tap-to-translate in the Reader sends the phrase you tap. In every case the input is sent on its own, without your name, email or account id, and the result is cached and reused, so it is not tied back to you. If you never open these features, nothing is sent.

If you subscribe to Pro, payments are processed by Stripe and your subscription status is brokered by RevenueCat. Your card details are handled by Stripe and are never stored on our servers — we keep only your subscription state and an internal billing id.

We rely on a small number of service providers to run Kotoba Dōjō: hosting and database, email delivery, payment processing, AI text and image generation, and — only with your consent — crash reporting and anonymous analytics. Each receives only the minimum data needed for its function and may not use it for its own purposes. A current list of these providers is available on request at privacy@kotobadojo.com.

Some of these providers operate outside the European Economic Area, mainly in the United States. Where your data leaves the EEA, it is transferred under the European Commission’s Standard Contractual Clauses or another approved safeguard.

With your consent, we use Sentry to capture crashes and a brief replay of the error (no passwords, no email, no auth headers — see the consent banner for what each category covers). We use PostHog for anonymous funnel analytics — keyed by an internal user id, not your email or name. You can change either choice at any time from Self → Cookie preferences.

You can delete your account at any time from Self. Deletion is immediate and cascades to every record we keep about you. You can also export your data as JSON from the same screen. You have the right to access, correct, export, and delete your data, and to object to processing.

We keep your data for as long as your account is active. If you stop using Kotoba Dōjō entirely — no training sessions for 24 months — we anonymize the account rather than letting it sit indefinitely: your email, name, avatar name and any billing identifiers are permanently removed and your sign-in is severed, while anonymous study statistics and any decks you contributed are kept and can no longer be traced back to you. You never have to wait for this — you can delete your account outright at any time from Self.

The data controller is Artsiom Chtrykov, the operator of Kotoba Dōjō, based in Poland (European Union). To exercise any of these rights, or to ask a privacy question, email privacy@kotobadojo.com. If you believe we have mishandled your data, you also have the right to lodge a complaint with your local EU data-protection authority.

Last updated: 28 July 2026 · Questions: privacy@kotobadojo.com