Privacy Policy

01Who we are

Tongda is a simplified Chinese learning app and the website at tongda.app, operated by One FortySeven Limited (“we,” “us,” “our”), with its registered office at Unit 909, Prosperity Millennia Plaza, 663 King's Road, Quarry Bay, Hong Kong. This policy covers the website, our emails, and the Tongda app, including test versions. One FortySeven Limited is the controller of the personal data described here.

You can reach us at privacy@tongda.app.

02What we collect

• Website analytics: usage data such as page URL, referrer, device and browser details, interactions like pageviews and clicks, interaction heatmaps, and the campaign parameters on the link you arrived on. This is measured without cookies, using a short-lived pseudonymous identifier (see section 06).
• Messages: anything you send us directly, including support and feedback emails, in-app support chat, and reports you submit about generated content, including the reported text, the reason, and any note you add.
• Account and study data, if you use the app: account identifiers, the email address and sign-in method you use, your name and profile photo if you add them or your sign-in provider shares them, onboarding answers, settings, timezone, learning progress, review history, streaks, the people, places, and things you add to your palette, and mnemonic scenes you keep.
• Generation inputs: the character or word you're studying, the palette entries you pick or write, any direction you type when regenerating, and the generated result.
• Diagnostics: error and crash reports, product analytics events, app performance and reliability telemetry, generation logs, and rate-limit records. In the app, analytics events include an approximate location, such as city or country, inferred from your IP address. The IP address itself is not kept with events. On Android, the app also records the campaign labels from the Google Play link you installed from.
• Device and notification data, when you opt in: a push notification token used to deliver review reminders, subscription reminders, and support replies.
• Purchases: your subscription status and purchase history, such as the plan, trial state, and renewal dates. Apple or Google processes the payment; we never see your card number or billing address. Our servers verify each purchase with Apple or Google, receive their updates about renewals, cancellations, payment problems, and refunds, and store your subscription status.
• Advertising measurement: app activity such as installs, app opens, sign-ups, onboarding completion, trials, subscription purchases, renewals, and refunds; product identifiers, store purchase records, purchase value and currency; and device and network details. Advertising identifiers are included only with the required permissions. On iOS, using your advertising identifier and tracking across other companies' apps and websites also requires Apple's permission. In the European Economic Area, the United Kingdom, and Switzerland, we collect this data only if you allow it. Elsewhere, advertising measurement is on by default, and you can turn it off. Your choice applies to this device.
• Privacy choices: your advertising measurement choice, the time you made it, whether you made it during onboarding or in settings, and the consent version, stored on your device. To decide which of these rules applies, the app reads the country of your App Store or Google Play account each time it starts; if it cannot read the country, the opt-in rule applies.

We do not collect contacts or precise location. We access your photos or camera only when you choose a profile photo, attach an image in support chat, or save an image from it.

03How we use it

• To provide Tongda: run the website, operate your account, schedule your reviews, generate mnemonic suggestions and scenes, deliver audio, and answer your support requests.
• To communicate with you: account, security, subscription, and support messages, such as a reminder before your free trial ends, and, if you ask for them, product news and tips about Tongda.
• To keep Tongda safe and working: prevent abuse, enforce rate limits, fix errors, and secure the service.
• To improve the product: understand how Tongda is used and make it better.
• To measure our advertising: understand which ad campaigns bring new learners, so we can run our own ads well. Tongda shows no ads inside the app.
• To meet legal obligations: keep records and respond to lawful requests.

We send product news and tips only if you tell us you want them. You can stop them at any time with the unsubscribe link in every email, and this does not affect your account.

04Who we share data with

We use the following services to operate Tongda and measure our advertising:

• Cloudflare: website and content hosting and security.
• Convex: app backend and database. Our backend verifies purchases with Apple and Google and stores your subscription status.
• Clerk: sign-in with your email address or a third-party provider such as Apple or Google, and your profile photo if you add one. When you use a third-party provider, that provider also processes your sign-in.
• Resend: our emails, such as the reminder before a free trial ends and product news and tips. Resend receives your email address, first name, and the message content.
• PostHog: product analytics, error and crash diagnostics, and monitoring of generation requests, including their inputs and outputs. PostHog also receives paywall and purchase events from the app, with the plan and store price, and subscription status changes from our backend. PostHog also chooses which version of a screen you see when we test changes. In the app, these records are linked to your account identifier.
• OpenRouter: routing generation requests to AI providers such as OpenAI to produce mnemonic suggestions and scenes. Section 05 explains the inputs sent, model training, and provider retention.
• Tenjin: advertising measurement, under the rules in section 02. Tenjin receives the advertising data described in section 02: app events, purchase events, and device identifiers, with your advertising ID only if you also give the required permission. Tenjin forwards conversion data to the ad networks we advertise with, such as Meta and Apple Ads, so they can measure our campaigns. Ad networks may also use this data for their own purposes under their own privacy policies, such as Meta's Privacy Policy. We do not share your email address, name, or study content with Tenjin. The store purchase records Tenjin receives contain the transaction and purchase identifiers from Apple or Google and a random billing identifier that we create for your account; none of them contain your name or email address. You can turn this off in Profile → Privacy → Preferences.
• Crisp: in-app support chat. Crisp receives your user id, an optional nickname, your messages and attachments, and, if notifications are allowed, a push token for replies.
• Expo: app updates, app performance and reliability telemetry, and, if you turn on notifications, push delivery via Apple's and Google's notification services.
• Apple: app distribution through the App Store and TestFlight, Sign in with Apple, in-app subscription payments, and push notification delivery. Apple processes installs, purchases, tester feedback, and any diagnostics you share with it under its own terms.
• Google: app distribution through Google Play, including its testing tracks, Sign in with Google, in-app subscription payments, and push notification delivery. Google Play links include campaign information to help us measure downloads. Google processes installs, purchases, and any diagnostics you share with it under its own terms.

These providers may store and process data in the United States, the European Union, and other countries whose data-protection laws may differ from your own. Where the GDPR or UK GDPR applies to a transfer, we rely on appropriate safeguards such as standard contractual clauses or an adequacy decision. Providers that act on our behalf may use personal data only to provide their services to us and must protect it under their agreements with us. Apple, Google, and the ad networks that receive data from Tenjin also process some data under their own terms, as described above.

If One FortySeven Limited is involved in a merger, acquisition, financing, reorganization, or sale of assets, personal data may be disclosed or transferred as part of that transaction, subject to this policy. We will notify you of material changes, including any change of controller.

05Generated content

Tongda uses OpenRouter to send generation requests to AI providers such as OpenAI. These requests include the character or word you are studying, relevant details from your palette, and any instructions you enter for generation.

We do not use your personal content to train AI models. We configure OpenRouter to exclude providers that use requests for model training. Providers may retain requests and responses under their applicable retention policies, including for security, abuse prevention, and legal compliance. We do not guarantee zero data retention.

Tongda also stores saved scenes and generation logs as described in this policy. Do not put secrets or sensitive personal information into prompts. Generated suggestions can be inaccurate or unexpected, and you choose what to keep.

06Cookies and device storage

Our website analytics does not use cookies or store analytics identifiers on your device. Our analytics provider PostHog groups events with a short-lived pseudonymous identifier derived from your IP address and browser, so visits are not linked across days. IP addresses are not kept with analytics events.

The website does not use advertising or cross-site tracking cookies.

The app stores sign-in information, settings, onboarding progress, privacy choices, and offline study data on your device. We save your advertising choice so it applies when you next open the app, until you change it or clear the app's local data. In the European Economic Area, the United Kingdom, and Switzerland, advertising measurement through Tenjin starts only after you allow it. Elsewhere it starts when you first use the app, unless you turn it off. On iOS, it starts only after you answer Apple's tracking permission request.

On iOS, we also use Apple's attribution services to measure campaign results without your advertising ID. Apple sends these results to Tenjin. These services operate separately from your advertising choice.

07Retention and deletion

We keep data only for as long as it serves the purpose it was collected for.

Your email address is kept in your sign-in account while the account exists. If you stop product news and tips, we keep a record of that choice so we do not email you again.

Account and study data is kept while your account is active. You can delete your account at any time:

1. Open Tongda and go to your profile.
2. Tap Delete account and confirm.

If you cannot sign in, you can request account deletion by emailing privacy@tongda.app from the address on the account.

Deleting your account removes your sign-in identity and your account and study data from our active systems, and removes your study data and sign-in from the device used to delete it. Any other local data is cleared when you uninstall the app. Deletion also turns off advertising measurement on this device. We retain that privacy choice so measurement stays off.

Backup copies can remain until they expire under the backup retention schedule. We may retain records needed to meet legal obligations, prevent abuse, or resolve disputes, for as long as those purposes require.

Account deletion does not automatically remove analytics, purchase, or support records held by our providers. These records remain until separately deleted or their applicable retention periods expire. PostHog removes generation request and response text after 30 days; other analytics events linked to your account identifier are kept for up to seven years, or until we delete them at your request.

To request deletion of personal data, contact privacy@tongda.app. We will assess your request, take the steps required by applicable law, and explain any limits.

Deleting your account does not cancel an App Store or Google Play subscription. Manage your subscription in the store.

08Your privacy rights

Where the GDPR or similar law applies, we rely on these legal bases:

• Contract: to create and operate your account, sync your study data, generate scenes, manage your subscription and its entitlements, and provide support.
• Consent: to send you product news and tips, and to collect advertising data and share it with Tenjin, which forwards conversion data to ad networks. Both are optional, and you can withdraw either at any time.
• Legitimate interests: to run cookieless audience measurement on the website, receive limited campaign attribution through Apple's privacy-preserving attribution services, prevent abuse, enforce rate limits, diagnose errors, and secure Tongda. You can object to this processing by contacting us.
• Legal obligation: to keep required records and respond to valid legal requests.

Depending on where you live, you may have rights to access, correct, delete, and receive a portable copy of your personal data, to restrict or object to certain processing, and to withdraw consent. You can delete your account yourself at any time, as described in section 07.

You can turn off Advertising measurement in Profile → Privacy → Preferences. This stops Tenjin and new advertising data sharing from this device. You can use Tongda either way. Withdrawing consent does not affect the lawfulness of processing carried out before withdrawal.

On iOS, Apple's tracking permission is an additional control. Allowing it does not override your Tongda choice. Refusing it stops use of your advertising ID, but measurement without that ID continues while your Tongda choice is on. On either platform, changing your device's advertising-ID settings does not turn off advertising measurement in Tongda.

Hong Kong. Under the Personal Data (Privacy) Ordinance, you may request access to and correction of your personal data, and you may complain to the Privacy Commissioner for Personal Data. Providing your email address is voluntary, but without it we cannot create your account. We use your email address for news and tips about Tongda only if you say yes when we ask, and you can withdraw at any time without charge by unsubscribing or emailing us. Access and correction requests go to privacy@tongda.app.

EEA, UK, and Switzerland. Where the GDPR or equivalent law applies, you have the rights above, we transfer your data outside these regions only with the safeguards in section 04, and you can lodge a complaint with your local data protection authority.

United States. Depending on your state, you may have rights to know, access, correct, and delete personal information and to opt out of its sale, sharing, or use for targeted advertising. We share advertising data with Tenjin, which forwards conversion data to ad networks such as Meta. Some US privacy laws classify this as "sale" or "sharing." You can opt out by turning off Advertising measurement in your privacy preferences. Your choice applies to this device; change it on each device where you use Tongda. You can also email privacy@tongda.app. We will not discriminate against you for exercising any right.

To make a request, email privacy@tongda.app. We may need to verify your identity for requests such as access or deletion. Where the law allows, you can use an authorized agent. We will respond within the time the law requires. If we decline a request, you can appeal by replying to our response and we will review the decision.

09Security

We use reasonable technical and organizational measures to protect personal information, such as encryption in transit and access controls. No method of storage or transmission is completely secure. If a personal data breach affects you, we will notify you and the relevant authorities where the law requires it.

10Children

Tongda is not directed at children under 13, and we do not knowingly collect personal information from children under 13. Users who are not old enough to consent to the processing of their personal data or enter a binding contract where they live may use Tongda only with permission from a parent or legal guardian. If local law requires parental consent, do not use Tongda until a parent or legal guardian has provided it. If you believe a child under 13, or a child using Tongda without required permission, has provided personal information to us, contact us and we will take appropriate steps to delete it.

11Changes

We may update this policy as the product, providers, laws, or platform requirements change. We will update the date above and, where appropriate, notify you of material changes.