String AI — Privacy Policy

String AI is an AI-powered practice app for violin, viola, and cello. This policy explains what we collect, what we never collect, and the rights you have. Questions: stringaiapp@gmail.com.

1. How we keep your data safe

Your phone does the heavy lifting. Pitch, rhythm, tone, dynamics, and posture are analyzed locally on your device. Only derived practice metrics and the limited optional content described below leave your phone. No raw audio or video is uploaded to our servers. Your music stays yours. How we protect what we store: data is encrypted in transit (TLS) and at rest; database rules let each account read and change only its own records, and parental-consent rules are checked on our servers as well as in the app; server keys are never included in the app; only the operator can access production data, and administrative database queries made with our tools hide identifying values; we check the app’s outgoing connections against a reviewed list before each release; and we review these safeguards at least once a year.

2. What we collect

Account: email, age range, a display name you choose (a nickname is perfectly fine), profile emoji, and app language. Store age signals: where available, we check the age range and approval status supplied by Apple or Google. We discard the original age bounds and declaration source after the check and do not cache them on the device. The updated app also removes caches left by older versions. We retain only the necessary protection decision and, for child or supervised accounts, a minimal installation-to-account link to process withdrawal of app approval. These links are deleted with the account. The device may retain a pending-approval flag and receipts for a specific significant update; these contain no age range. Store age information is not used for advertising, marketing, analytics, or profiling. For an account the store has confirmed as 18 or older, we keep only the time of that confirmation and the identifier of the current significant update, per account, in this device’s app cache, so that we ask for the age category no more than once every 12 months. It contains no age range, declaration source, or installation details and is never sent to our servers. Even the file name is a value that does not reveal the account identifier. It is deleted when you delete your account or remove the app, when the account becomes one we must check every time, and when it can no longer be used (after 12 months, when a new significant update is released, when the device clock is set back before the recorded time, when the record is malformed, or when the device newly supports the store’s significant-update check). Signing out alone does not delete it, so signing back in to the same account does not ask again within the 12 months. Other accounts (under 14, supervised, awaiting approval, or where the store did not share an age range) are checked each time the app opens, without this record. Practice settings: your instruments (there can be more than one) and the level for each, instrument size, daily goal and its change history, practice days, vibrato experience, and music terms already explained. Practice metrics: practice dates, pieces, and time; scores for pitch, rhythm, dynamics, tone, and posture; observed interruption counts and assessed-range completion for each measure; mission attempts; and the instrument and level of that practice. Class progress (Ear Training, Music Theory, Music History, Vibrato): completed units, accuracy, stars, attempt counts, and each attempt’s result and completion time. Schedules and favorites: pieces you picked with the practice period, weekdays, daily minutes, and measure range, and pieces you marked as favorites. Practice journal: when leaving the Practice Room, a student may choose a mood (one of three) and write a short note (up to 300 characters). These practice journal notes and mood are saved on our servers with that practice record, and a linked teacher can see them (see section 9). Notes that look like an email address, phone number, or link are not saved. For students under 14, they are sent to our servers only if a parent has agreed to the September 24, 2026 notice (the first to list them) or a later one; before that, they are kept only on this device for the account, are never uploaded later, are included in the personal data export, and are deleted when account or consent data is deleted. Optional server content: score markings you draw and a short musical teaching note entered by a linked teacher. Piece requests: the title, composer, instrument, and short note you type when asking for a piece that is not in the library. Feedback: the category (feature idea, problem, other) and text you send through the in-app feedback form, plus the app version, device type (iOS/Android), and update channel attached automatically so we know which build you mean. We ask you not to include names or contact details; if a reply is needed, we use your account email. AI lesson records: the derived metrics sent and the coaching text received when coaching is generated (see section 4), and daily AI feature usage (call counts and voice characters). App service info: trial and subscription status (see section 11), app version, build, update channel, and device type (iOS/Android), a device push token for notifications and the device time zone, and records of update notice emails we sent. The device time zone is used only to hold notifications between 10 PM and 9 AM and send them in the morning; if a student’s time zone is not known, the connected teacher’s time zone is used instead. For students under 14, the device time zone is stored only after a parent has agreed to a notice that lists it. Connection info: each time the app downloads material such as the piece list, scores, videos, or app version information from our server (Supabase), or guide videos from our website (stringaiapp.com, hosted on GitHub Pages), the request carries connection information such as your IP address and device and app type, as every internet request does, and it may remain briefly in server logs kept for security and to operate the service (GitHub's logs follow the GitHub Privacy Statement). We do not use these logs for advertising, marketing, analytics, or profiling. To stop abuse, some requests that could be repeated excessively, such as entering an invite code, leave a short server record of only the request type, the account, and the time, which is deleted within two days at most. Reports: if you report a connected teacher’s or student’s note, score markings, practice journal note, or the person in the app, we store the reporting account, the account that wrote it, the kind and location of the content (which piece or practice), the reason you chose, and its handling status and times. We do not copy the reported content itself. Our operator is told only that a report came in (its kind, reason, and time), by email and an alert. Consent records: the parent email, consent, renewal-request and withdrawal times, notice version, and consent method used to obtain and apply parental consent; for a student under 14, the parent’s choice on AI coaching (international transfer) and its time (see section 5); teacher-connection approval records (see section 9); the wording version of the analytics consent you agreed to; and, for teacher accounts, the version and time the teacher confirmed the teacher commitments (see section 9). Device-only content: Class steps, response states, and active time are saved on this device for the account so an unfinished unit can resume; they are never uploaded. Intermediate records are removed when the attempt is completed or account or consent data is deleted, and are included in the personal data export. Practice Room videos are created when you start recording and are saved on the device when recording ends; they are kept in this account’s folder on this device and are never uploaded (see section 3). During a lesson, a temporary replay of your takes (video, when the camera is on, and sound) is kept in the app’s cache on this device so you can watch it back; it is deleted when the lesson ends, or the next time the app opens if it closed unexpectedly, and is never uploaded. Crash diagnostics: if the app stops unexpectedly, a crash report (device model, OS version, app version, a randomly generated SDK installation identifier, and the technical error trace) is sent so we can fix it. We do not attach your account ID or email. Reports may be linked to the same app installation; they are not used for advertising or tracking across other apps and contain no practice recordings. Parent adult verification: where needed for teacher sharing, we send the parent’s email, the child’s country of residence, the notification language, and a random request reference to KWS when the parent requests verification. String AI retains the verification status, transaction reference, verification time, disclosure version, and link to the relevant consent request. We do not receive the original card details, identity documents, or national identification numbers used for verification.
Legal bases (what we process without consent and what we process with consent — Articles 15, 17 and 22(3) of the Personal Information Protection Act):
• To perform our contract with you (Article 15(1)(4), no consent needed): your account, practice settings, practice records and practice journal notes and mood, class progress, schedules and favorites, score markings, piece requests and feedback, teaching notes and homework from a connected teacher, your trial and subscription and daily AI feature usage, a device token and time zone for notifications, and service emails — needed to provide the practice service you signed up for.
• To meet legal obligations (Article 15(1)(2), no consent needed): records of how parental consent was obtained and kept (consent records), and the subscription transaction record kept after account deletion (e-commerce law — section 7).
• For legitimate interests (Article 15(1)(6), no consent needed — only as far as needed to keep the service and its users safe, and never for other purposes): reports, abuse-prevention records, crash reports, and connection information.
• With consent (Article 15(1)(1)): [Optional] analytics consent (AI lesson records), [Optional] AI coaching international transfer (Article 28-8(1)(1) — sections 4 and 8), sharing with a teacher you connect with (Article 17(1)(1) — the student chooses to connect by entering the invite code, and for a student under 14 a parent approves each teacher — section 9), and parent adult verification when a parent requests it (section 8). Consent can be withdrawn at any time, and refusing an optional item does not stop the core features.
• Students under 14: we process even the contract items above only after a parent consents (section 5). Before that, we process only the minimum account and contact details needed to ask for consent, store age signals, reports, and the connection information that comes with every internet request; for children under 13 in the United States, this stays within what COPPA allows before parental consent: contact details used to obtain consent (16 CFR §312.5(c)(1)); reports, used only to protect the security and integrity of the service and to take precautions against liability (§312.5(c)(6)(i)–(ii)); and connection information and the store installation link, which are persistent identifiers used only to support internal operations such as security, integrity, and legal compliance (applying age and consent protections and withdrawals of app approval) (§312.5(c)(7)). We do not use these persistent identifiers to contact a specific person, for behavioral advertising, or to build a profile of a specific person: connection information stays only briefly in server logs, and the installation link is used only for the protection decision and to process withdrawal of app approval, and is deleted with the account.

3. What we never collect

We never collect raw audio or video or upload it to our servers. The only raw video kept on your device after a lesson is a recording you make in the Practice Room, which is saved in this account’s folder on your own device; it is never sent to us and is removed when you delete the account. Lesson replays are temporary and are deleted when the lesson ends (section 2). It may still be included if you back the device itself up to iCloud or your Google account — that backup is yours, not ours. We also never collect your address, phone number, school, or identity documents. The display name you pick can be a nickname — we never require or verify your legal name. We do not sell or rent any data to third parties. Information provided directly to KWS and its verification providers when a parent chooses adult verification is described separately in section 8. When you choose Save video, String AI adds a copy to the device photo library using the operating system’s media-saving API. The recording feature does not offer messaging, social-network, or other-app sharing and does not read your existing photos. A photo-library copy remains after the recording or account is deleted in String AI; you can delete that copy in your photo app. Photo-library cloud syncing follows your device and photo app settings.

4. AI coaching (OpenAI)

We use OpenAI's API for two things, and only with your consent to the international transfer (for a student under 14, a parent chooses this separately — see section 5): writing coaching text such as piece introductions and practice plans, and reading the app’s coaching sentences aloud in a natural voice. To write coaching text, we send derived practice metrics, public score context, and, when provided, the short musical-focus note written by a linked teacher; to read coaching aloud, we send the text of the sentence. Scoring and weakness diagnosis are worked out on your phone, and the feedback after each take uses sentences prepared in the app — if the natural voice is on, only their text is sent, to be read aloud. Without this consent, coaching uses the app’s built-in sentences and your device’s voice. We never send raw audio or video, account name, email, or user ID. Email addresses, phone numbers, web links, and social handles are blocked from teaching notes before they can be saved or sent; teachers are also told not to enter names or sensitive information. Score drawings are never sent to OpenAI. By default, the OpenAI API does not use API data to train its models. Data may be retained for at most 30 days for abuse monitoring and is then deleted unless law requires otherwise.

5. Children and parents (under 14)

Students under 14 require a parent or guardian's explicit consent before practice data is collected. A parent can give consent by pressing the button in the consent request email. AI coaching (international transfer, sections 4 and 8) is a separate choice the parent makes on the consent page (it starts off); the app works without it, and the parent can turn off just this with the link in the confirmation email. Reports (section 2) are a safety feature, so they can be made before parental consent or after it ends, and they are kept until handled even when records are deleted because consent ended (section 7). Before consent, we process the limited account/contact details needed to request consent and store age signals needed to apply or revoke that consent. Parents can view, export, or delete their child's data at any time from Profile > Privacy & Data. A parent who does not have the child’s device can email the privacy officer in section 13 from the parent email address on file. Parental consent is valid for one year. About 30 days before it ends, we email the parent a request to renew it. If it is not renewed by then, we stop collecting the child’s practice data, the teacher connection ends (a renewed consent needs the teacher approved again), and the records already saved are kept locked for 30 days — not used or shared — so a parent can still renew and keep them; after that, they are deleted. If a parent does not consent again within 12 months after consent ends or is withdrawn, we also delete the remaining account (account details, practice settings, and consent records) (section 7). We comply with COPPA (US, age 13) and PIPA (Korea, age 14), using the stricter 14-year threshold globally. Adult verification for teacher sharing is separate from final approval to share with that particular teacher (sections 8 and 9). Adult verification alone does not approve sharing. Public availability: String AI has no feature for children to make personal information publicly available (no public profiles, public posts, or public rankings). Practice records, practice journal notes, and teaching notes are exchanged only with a teacher the student chose to connect with (for students under 14, a teacher the parent approved), and piece requests, feedback, and reports go only to our operator. A student can save or send their own certificate or data export file through the device’s share menu; what happens after that is outside String AI.

6. Your rights

You can: (1) access and review what's stored about you, (2) export a portable JSON copy from Profile > Privacy & Data — your profile, subscription, sessions and scores, practice time, daily goal history, schedules, favorites, class progress, AI interactions, piece requests, feedback, score markings you drew, teacher connections and teaching notes, notification devices, consent records, practice journal notes and mood (both those saved on our servers and those kept only on this device), and this device’s class resume state; for access to other personal data, contact our privacy officer, (3) correct inaccurate data, (4) delete your account permanently, including its account-scoped data on this device, (5) withdraw analytics consent without losing core features (the AI lesson records saved so far are deleted), and (6) object to or restrict certain processing. We give these rights to every user, wherever you live; the law where you live (such as PIPA in Korea or the GDPR in the EU) may give you more. You can also lodge a complaint with your data protection authority (section 13).

7. Data retention

How long we keep each kind of data: account and settings — while the account exists (for a student under 14, until 12 months after parental consent ends or is withdrawn — see below); practice records, class progress, practice journal notes and mood, schedules, score markings, piece requests and feedback — while the account exists, and for a student under 14 only while parental consent is valid plus the 30-day lock after it ends (section 5); AI lesson records — only while analytics consent is on (withdrawing it deletes them); consent records — while the account exists, so that each consent or withdrawal can be shown and respected; crash reports — up to 90 days at Sentry; reports — one year from when they are handled (or received, if not handled), deleted with the reporting or reported account (they remain until handled even when an under-14 student’s records are deleted because consent ended, for safety); abuse-prevention records — two days at most; device-only content — until it is completed or deleted, or the account or the app is deleted. Account deletion: all personal data is deleted within 30 days, except the subscription transaction record described below, which is kept without account details for the legally required period; anonymized aggregate metrics may be kept for product improvement (no link back to you). Subscription payments are processed by Apple or Google, which keep your payment method and payment history. When you delete your account, we remove your account details from the subscription record we hold; if a store purchase was made, we keep only that transaction record (store, store transaction ID, product, subscription period, whether it was cancelled, and the deletion time), separately from other data, for 5 years from the end of the subscription period (or the deletion date, if later), as Korean e-commerce law requires for payment and supply records, and then delete it. We use it only for legally required verification and disputes and never link it back to an account. Records the app keeps for your account on another device are removed when you delete the app on that device. Copies in our operator mailbox: piece requests are also emailed to our operator, and in-app feedback sent before October 12, 2026 may also have been emailed. These email copies are not removed automatically by account deletion or by consent withdrawal or expiry; if you ask us by email to delete your data, mention them and we will delete them too. If parental consent is never obtained: a consent request expires 7 days after it is sent, and if consent is still not confirmed 30 days after that expiry, we delete the student's account and its data. Before consent we do not collect practice data (see section 5), so the only information held during this period is the contact details, account record, and limited store age/installation signals needed to obtain and enforce that consent. If an under-14 student’s parental consent ends: saved practice records are deleted right away when consent is withdrawn, or after the 30-day lock when it expires (section 5); if a parent does not consent again within 12 months after consent ends or is withdrawn, we also delete the account and what remains with it (account details, practice settings, consent records, and the store age-signal link), in the same way as account deletion (including the subscription transaction record exception below). A KWS verification request expires after at most 24 hours or when the related sharing request expires, whichever comes first. Requests more than 30 days past expiry are cleaned up daily, except that successful verification evidence is retained while the approved teacher relationship remains active. Deleting the student account or related approval record also deletes its linked verification records. Retention and deletion in KWS’s separate AgeGraph follow the KWS policy described in section 8 and are not automatically linked to deletion of a String AI account. How we delete: deletion on our servers runs automatically (account deletion, consent withdrawal or expiry, and daily clean-up jobs), and deleted records cannot be restored from the app; data kept only on a device is deleted by the app on that device; backups kept by our database provider are overwritten on its regular schedule.

8. Service providers and international data transfer

We rely on a small number of service providers (processors) solely to run the service, and we use KWS for parent adult verification. These providers are in the United States (KWS is in the United Kingdom), so for users elsewhere, including in Korea, using String AI involves transferring personal information abroad. Each recipient, what it receives, and how:
• Supabase, Inc. (United States; contact: https://supabase.com/privacy) — database, sign-in and hosting: account data, practice metrics, optional teaching notes, score markings, piece requests, feedback and the other server data in section 2. When: whenever the app or our servers store or read your data. Purpose: storing and running your account. Retention: while your account exists; deleted within 30 days of account deletion.
• OpenAI, L.L.C. (United States; privacy contact: https://openai.com/policies/privacy-policy) — the coaching context and the text to be read aloud described in section 4. When: in real time, each time AI coaching is written or read aloud. Purpose: AI coaching text and its voice. Retention: at most 30 days. This transfer happens only with consent (for a student under 14, a parent’s).
• Sentry (Functional Software, Inc.; United States; contact: https://sentry.io/privacy/) — crash reports and a randomly generated SDK installation identifier; we do not attach your app account ID or email. When: when the app stops unexpectedly. Purpose: finding and fixing bugs. Retention: up to 90 days.
• Expo (650 Industries, Inc.; United States; contact: https://expo.dev/privacy) — app update delivery through EAS Update (operating system information and randomized tokens to measure update downloads) and remote push delivery (the device push token and notification text), relayed through the device operating system’s push services, Apple (Apple Push Notification service) and Google (Firebase Cloud Messaging). On Android, when you allow notifications and the device registers, Google’s Firebase receives an installation identifier and basic device and app information directly; we do not receive those values. We do not attach your app account name or email to update requests. Practice alerts sent to a linked teacher may include the student’s display name and practice activity. When: when the app checks for updates or a notification is sent. Purpose: delivering updates and notifications. Retention: only as long as needed to deliver them.
• Resend (United States; contact: https://resend.com/legal/privacy-policy) — sending the emails this service issues: account emails such as sign-up confirmation and password reset, the parent-consent email with its reminders, related notices and renewal requests, the parent’s teacher-connection approval email, piece-request decisions, new-version notices and operator alerts; it receives only the recipient’s email address and the message itself. Each email carries a tiny open-tracking image, so only whether and when the email was opened is recorded — never your location or device details; to prevent this, turn off automatic image loading in your email app (the email still works). When: each time we send an email. Purpose: delivering service emails. Retention: delivery records for a limited period under Resend’s policy.
• Kids Web Services Ltd (KWS) (United Kingdom; contact: https://www.kidswebservices.com/privacy-policy) — parent adult verification, described below. When: when a parent requests verification.
All transfers use TLS encryption over the internet, and stored data is encrypted. Legal basis: transfers to the service providers above are made to run the service under our contracts with them and are disclosed in this policy (for users in Korea, entrustment and storage abroad under Article 28-8(1)(3) of the Personal Information Protection Act); the optional AI coaching transfer to OpenAI is made only with consent (Article 28-8(1)(1)). Where data is transferred outside your region, we rely on appropriate legal safeguards. How to refuse, and what happens: you can turn AI coaching off in Profile at any time (for a student under 14, a parent can withdraw it), and coaching then uses the app’s built-in sentences and your device voice; you can turn notifications off in your device settings; processing by Supabase, Resend, Expo update delivery and Sentry is needed to provide the service, so to stop it you can delete your account (section 6). We do not sell or rent personal information. We use KWS, provided by Kids Web Services Ltd in the United Kingdom, for parent adult verification. When a parent requests verification, we transmit the limited information in section 2 over an encrypted connection. KWS processes the request email and acts as a separate data controller for adult verification and AgeGraph when the parent interacts directly with KWS. Depending on the chosen method, KWS and its verification provider process the parent’s identity or payment information directly; String AI does not receive the original details. KWS retains a hashed email and minimal verification records, such as status, method, and time, in AgeGraph to reduce repeat verification across participating services. This does not make the data anonymous. Processing may involve KWS group companies and service providers in the United States and other countries. See https://www.kidswebservices.com/privacy-policy and its provider list for verification providers, international transfers, retention, and deletion. You can request AgeGraph removal using the opt-out link in your KWS verification confirmation email or KWS’s privacy contact channel. You may decline this verification and teacher sharing; the teacher connection will not be completed, while already-authorized individual practice remains available. Beyond our service providers, disclosures such as this KWS verification and the optional teacher sharing in section 9 are specifically described and subject to any required consent.

9. Sharing with your linked teacher (optional)

String AI lets a student connect with their teacher by entering the teacher’s invite code. Connecting is optional. While connected, the teacher can see the student’s display name, emoji and in-app connection identifiers; instrument and level; practice and class study dates, pieces, time and streak; practice journal notes and mood; session and measure scores and weakness summaries; and daily time goals, practice schedules and homework progress. Teachers who enable alerts may receive the student’s display name and updates about practice starting or inactivity in notifications. Audio, video, login email addresses and parent email addresses are not shared with the teacher. Practice Room recordings are kept on the device and are never uploaded or shared with the teacher; a copy the student saves to the photo library follows the device’s photo settings (section 3). Under the “Teacher accounts” paragraph of our Terms of Service (which takes effect on October 18, 2026; its device-security commitment takes effect on November 11, 2026), teachers agree to use student information only to teach that student, to keep it confidential and not share it outside the app, not to use it to contact students or parents for unrelated purposes, to stop using it and delete any copies when the connection ends, and to keep the devices they use to see it secure (for example, with a screen lock) and not alter or spread it; from app version 1.0.3, the app asks each teacher to confirm these commitments before showing the student list and records in the app, and a teacher who confirms them in the app is bound by them from that confirmation, even before those dates. A connected teacher can assign practice plans and write short teaching notes. If the student’s app is up to date, teaching notes are shown to the student as written, on the student’s practice plan screen. A connected teacher can also send the student a practice reminder with fixed app wording, at most once a day (the teacher does not write the message). Teacher score markings appear as a separate read-only layer; the student’s own score markings remain private. For students under 14, a parent or guardian must first consent to app use and then approve the particular teacher connection by email. Practice information is not shared before approval, and the parent may decline. You can disconnect at any time in Profile > My Teacher, which stops sharing the student’s profile and practice records. Students can report a teacher’s notes, score markings, or the teacher, and teachers can report a student’s practice journal note or the student, in the app (section 2). Teacher-authored notes and score markings may remain available to their author. Student-specific notes are deleted with the student’s account; the teacher’s own piece-level score markings are stored separately from that account. Where parent adult verification is required, it must be completed before final approval of that teacher connection.

10. Posture (biometric) data

When the camera analyzes posture and bowing, your phone computes body-position (posture) measurements. Because these may qualify as biometric information, we disclose them separately. What: posture angles derived from body keypoints (positions of shoulders, arms, wrists, etc.). In posture analysis, the positions of the eyes, ears, and corners of the mouth are used only to calculate head tilt and raised shoulders. To find a person in the frame, the model checks whether a face is present, but it does not recognize who anyone is, measure the shape of the face, or create face data (a template), and these positions are never stored or sent off the device. Why: solely for posture and bow-technique coaching. Where: processed entirely on your phone (offline) — neither the raw video nor the body keypoints are ever transmitted off the device. Retention & destruction: each frame used for posture analysis is discarded immediately after analysis, and the body keypoints are never stored; only the session score (numbers) remains. (A separate temporary lesson replay can keep video on the device until the lesson ends — section 2.) We never sell or share this data with third parties. Camera permission authorizes access to the camera; it does not by itself replace any separate consent required by law. You can revoke camera access in device settings; you can still take lessons, and only posture is not measured. If you separately choose to record a performance, that local recording follows the recording and deletion rules in Section 3.

11. Subscriptions and payments

String AI offers auto-renewing monthly subscriptions purchased through the Apple App Store or Google Play. All payment processing is handled entirely by Apple or Google — we never receive or store your credit-card, bank, or billing details. To activate and verify your subscription, we receive a transaction identifier and the product you purchased from the store, and store it linked to your account. We use this only to grant your membership, restore your purchases, and meet tax and accounting obligations. If you delete your account, only the transaction record, without your account details, is kept for the legally required 5 years (section 7). Renewal, cancellation, and refund terms are described in our Terms of Service. On Android, when the app prepares Google Play billing or you make a purchase, the Google Play Billing Library sends diagnostic information about how the billing feature is working directly to Google. We do not receive this information; Google processes it under the Google Privacy Policy (https://policies.google.com/privacy).

12. Changes to this policy

We may update this Privacy Policy as the app evolves or as the law requires. When we make a material change (for example, collecting a new type of data or adding a new processor), we will revise the effective date at the top of this policy and, where required, ask affected students or parents to review and re-consent inside the app. Where a change requires fresh consent by law, we begin the relevant processing only after obtaining it; continued use alone is not consent.

13. Who we are and how to contact us

String AI is the data controller responsible for your personal data. The operator’s name, postal address, and telephone number are published with the web version of this policy (https://youna-string.github.io/stringai-legal/privacy-policy.html). Privacy officer: String AI Privacy (stringaiapp@gmail.com). For any privacy request — access, export, correction, deletion, withdrawal of consent, or a complaint — contact the privacy officer. We respond within 7 days. For urgent privacy issues (suspected data breach, parental concerns), please mark the subject line as PRIVACY URGENT. If you are not satisfied with our response, you may also contact your data protection authority (in the EU/EEA, your local supervisory authority; in the Republic of Korea, the Personal Information Protection Commission and the Personal Information Dispute Mediation Committee).

Operator (online notice under the Children’s Online Privacy Protection Act and the operator responsible under section 13): Youna Choi · 4708 Oakwood Ave. Apt 206, Los Angeles CA 90004 · +1-213-210-4792 · stringaiapp@gmail.com