Privacy policy

Overview

Data we handle

Account information

Nihongo uses passwordless email sign-in. We process your email address, authentication records, and one-time verification codes to create and secure your account.

Learning progress and app activity

When you use the iPhone app, Nihongo stores your kana and vocabulary progress, saved study and practice sessions, answers, scores, timings, favourites, and aggregate time spent. This lets the app preserve your progress and show recent or best results.

Translations and translation history

Text you enter in the app, or Japanese text you actively select in Chrome, is sent to Nihongo’s translation service. The resulting translation, reading, phrase breakdown, and kanji details are returned to you and saved in the appropriate app or Chrome translation history.

Photos, images, and pronunciation recordings

If you choose image translation, the selected photo or image is uploaded for processing and may be saved with its result in your recent translation history. If you choose pronunciation practice, one short microphone recording is sent for transcription and assessment. Nihongo does not keep that pronunciation recording after the request completes.

Account-linking information

QR linking associates the extension with your signed-in Nihongo account. Nihongo stores a general device label (for example, “Chrome on macOS”), session creation and last-used times, and a one-way hash of the browser session token. The token itself stays in Chrome’s extension storage.

Local extension data

The extension stores your linked-session token, chosen auto-convert websites, and a short-lived exchange-rate cache in Chrome’s extension storage. When you keep a translation overlay, the extension also saves the selected Japanese text, its rendered translation, a short surrounding-text anchor, and that page’s address so it can restore the overlay when you return. This local cache is limited to 12 translations on each of the 20 most recently used pages. It is not uploaded to Nihongo and does not create a server-side browsing log.

Yen conversion

Yen detection and conversion happen in your browser. Nihongo requests the current JPY-to-USD rate, but does not send page text, prices, or the page URL with that request.

How data is used

• Create, authenticate, and protect your Nihongo account.
• Save learning progress, practice results, and preferences.
• Provide the translation you requested.
• Evaluate a pronunciation attempt you deliberately record.
• Show recent app and Chrome translations in your history.
• Link, authenticate, manage, and secure browser sessions.
• Apply rate limits and protect the service from abuse.
• Fetch a current exchange rate for local yen conversion.
• Diagnose crashes and service errors without default PII.

Nihongo does not use app or extension data for advertising, credit decisions, or unrelated profiling.

Service providers

Nihongo uses service providers only to operate the features described in this policy:

• Convex provides the application backend, account-linked storage, and session infrastructure.
• OpenAI processes actively selected Japanese text, app translation requests, translation images, and short pronunciation attempts to generate the requested result.
• Resend delivers passwordless sign-in codes to the email address you provide.
• Sentry helps diagnose crashes and service errors. Nihongo configures it not to send default personal information or translation inputs and outputs.
• Frankfurter provides the JPY-to-USD exchange rate. No selected text or webpage content is sent to it.
• Google Chrome provides the extension platform and local extension storage.

Retention and your controls

• App and Chrome translation histories each keep the 12 most recent unique items. Older items and their stored media are automatically deleted.
• You can delete an individual translation from History in the Nihongo app.
• Unfinished image-translation uploads and processing jobs expire after 24 hours. A completed image retained in recent History follows the 12-item history limit.
• Learning progress, saved sessions, practice results, and usage totals remain associated with your account until you delete them where a control is available or ask us to delete your account data.
• Browser sessions expire after 180 days. You can unlink from the extension or revoke a browser from the Nihongo app at any time. Ended session records are removed after up to seven days.
• Saved Chrome overlays are removed individually when you close their translation card or chip. The local cache keeps at most 12 overlays on each of the 20 most recently used pages.
• Pairing codes expire after five minutes. Approved pairing records are retained briefly so the browser can finish linking, then removed.
• Removing the extension or clearing its data removes locally stored extension settings and credentials.

For other access or deletion requests, contact us at the address below.

Security

Nihongo uses short-lived pairing codes, randomly generated browser credentials, one-way token hashes on the server, scoped extension storage, session expiration, revocation controls, and rate limits. No security measure is perfect, but we design the app and extension to minimize the data they send and store.

Contact

Questions, privacy requests, or support issues can be sent to:

We may update this policy as Nihongo changes. The effective date at the top of this page will change when we publish an update.