Terms of Use

1. Provider, Scope, and Acceptance

KyouStudy is provided by HungBok ("HungBok," "we," "us," or "our"). These Terms of Use ("Terms") apply to the KyouStudy mobile application for Android and iOS, kyoustudy.com, KyouStudy-operated image-delivery and content-reporting services, and related support (collectively, the "Services").

By downloading, installing, purchasing, accessing, or using the Services, you agree to these Terms and the Privacy Policy. If you do not agree, do not use the Services. The terms presented by Apple App Store, Google Play, a purchase screen, or another third-party service also apply to your relationship with that provider. Mandatory consumer rights prevail over any conflicting provision in these Terms.

2. Eligibility

You must be at least 13 years old and meet any higher minimum age required in your country to use the Services on your own. If you are below the age of legal majority, a parent or legal guardian must review and agree to these Terms and supervise your use. The Services are not directed to children under 13.

You represent that you may lawfully use the Services, that you are not prohibited from receiving them under applicable law, and that information you provide in a purchase or support request is accurate.

3. The Service and KyouStudy Accounts

KyouStudy is an offline-first language-learning tool for courses and materials associated with JLPT, TOEIC, TOEFL, IELTS, HSK, TOCFL, TOPIK, and general language study. Features may include study cards, vocabulary and character content, readings, meanings, examples, pronunciation, stroke-order displays, quizzes, wrong-answer review, bookmarks, collections, goals, statistics, streaks, reminders, and generated collector-card images.

Core study features ordinarily work without a KyouStudy account. Learning records and settings are primarily stored on your device, but optional account, backup, sync, transfer, content reporting, or other connected features may process selected information remotely. Platform purchase, backup, text-to-speech, remote image, content-reporting, photo, sharing, notification, analytics, and advertising features may require an Apple Account, Google Account, installed engine, permission, consent, internet connection, or other platform service. We do not promise that every advertised course or feature is available in every build, platform, region, language, or free/Premium tier.

4. Limited License to Use the App

Subject to these Terms and the applicable app-store rules, HungBok grants you a personal, limited, non-exclusive, non-transferable, non-sublicensable, revocable license to install and use KyouStudy on devices that you own or control for personal, non-commercial study. Apple family or volume-use rules and Google Play family or device rules apply where the relevant store permits them.

You receive a license to use the app, not ownership of the app or its content. Separate open-source, data, audio, font, artwork, and platform licenses described in Section 16 govern the materials to which they apply and take priority over this limited license if there is a conflict.

5. Your Responsibilities

• Use the Services lawfully, for genuine personal learning, and in accordance with exam, school, employer, and platform rules that apply to you.
• Protect your device, platform account, backups, saved images, purchase credentials, and any information you choose to share.
• Review study answers, translations, readings, pronunciation, stroke data, statistics, and reminders before relying on them.
• Maintain independent copies of any record you consider important. Local storage, backup, cache, import, and device-transfer features are conveniences, not guaranteed archives.
• Install security, operating-system, app, content, and compatibility updates reasonably needed to continue using a feature.

6. Educational Content, Accuracy, and Results

KyouStudy provides study assistance, not an official curriculum, score report, certification, translation service, dictionary authority, accessibility accommodation, or professional educational advice. Course levels and labels are organizational aids. Official syllabi, scoring, registration, identification, permitted materials, test-day rules, and results are controlled by the relevant exam organization.

Language data can contain omissions, disputed classifications, regional variants, outdated forms, alternative readings, imperfect translations, unnatural examples, incomplete audio, image errors, or technical defects. Text-to-speech and recorded audio may differ from natural pronunciation. Character and stroke forms can vary by region, font, standard, and writing convention. We welcome corrections but do not guarantee that the content is complete, current, or error-free.

Some voices, pronunciation assets, illustrations, or study images may be generated, synthesized, enhanced, or otherwise assisted by artificial-intelligence tools and then selected, arranged, edited, or reviewed for KyouStudy. Such material may contain artifacts or inaccuracies and must not be treated as an authentic recording, photograph, statement, endorsement, or identity of a real person unless expressly identified as such.

Your results depend on many factors beyond the Services. KyouStudy does not guarantee learning progress, fluency, admission, certification, a particular score, or success on any examination.

7. Exam Names, Organizations, and Third-Party Marks

KyouStudy is an independent study tool. It is not an official app of, affiliated with, sponsored by, approved by, or endorsed by any exam organization. Exam names and trademarks, including JLPT, TOEIC, TOEFL, IELTS, HSK, TOCFL, and TOPIK, belong to their respective owners. Their use identifies the study area or exam for which material is organized and does not imply a relationship with HungBok.

Other names, logos, flags, symbols, typefaces, product names, and marks displayed in the Services belong to their respective owners. Unless expressly stated, their appearance is informational or descriptive and does not imply endorsement. You may not extract or reuse third-party marks from KyouStudy except as independently authorized by the owner or applicable law.

8. Device, Network, Content-Reporting, Notification, TTS, Photo, and Sharing Features

Optional study images may be downloaded from img.kyoustudy.com over HTTPS and cached on your device. Availability depends on the network, host, requested file, cache, and device. We may remove or replace remote content, and a cached copy may be older than the server copy.

Features that connect to KyouStudy or third-party servers include remote image delivery, content-problem reporting, app-store purchase and entitlement checks, analytics, advertising and consent management, website access, optional support or sync, remote notifications where offered, and a network-based TTS engine selected on your device. Network requests may transmit ordinary connection information such as an IP address, request time, protocol, and user agent to the relevant infrastructure. Mobile data, roaming, internet-provider, or other connection charges remain your responsibility.

Content-problem reports

Study and quiz screens may let you report a problem by choosing one of the displayed report types. Opening the report menu does not send a report. Selecting a type sends the report immediately without a separate confirmation or free-text description. The submission includes the selected type; the affected course, level, content and question identifiers; a snapshot of the affected expression, reading, meaning, explanation, image or audio metadata and, for quizzes, the prompt, choices and expected-answer data needed to investigate the issue; app version and build; Android or iOS and OS version; general device type and model; interface and study languages; UTC offset; and a random request identifier.

Content reports do not require an account and are not designed to include your name, email address, advertising identifier, permanent device identifier, serial number, precise location, attachment, free-text description, or complete learning history. We use reports to reproduce, review, correct, reject, or consolidate reported issues and to protect the reporting service from abuse. Live report records are kept for no more than six months; reports marked fixed, duplicate, or rejected are scheduled for deletion within three months after that decision and never later than the original six-month limit. Provider recovery history may retain a deleted database state for the limited backup period described in the Privacy Policy.

Pronunciation may use bundled recordings or the operating system's or installed provider's text-to-speech engine. An engine may synthesize locally or send text over a network under its own terms. Voice availability, pronunciation, data handling, and charges are controlled by the selected provider.

Notifications are optional and are ordinarily scheduled locally; KyouStudy may also use platform push services for features that require remote delivery. Delivery time is not guaranteed. Network conditions, provider availability, battery controls, exact-alarm permission, clock or time-zone changes, reboots, focus modes, and system settings may delay or suppress a notification. Notifications can include learned expressions, streak information, service messages, or other content visible on the lock screen, so configure notification privacy on your device if needed.

When you save or share a collector card, you direct the app to create an image containing visible learning content and pass it to your photo library or selected share destination. You are responsible for the recipient, privacy, copyright, and later distribution of that image. KyouStudy does not control or track the destination after handoff.

9. Premium Plans and In-App Purchases

When available, KyouStudy may offer the following products through Apple App Store or Google Play:

The purchase screen identifies the product, included benefits, localized price, billing period, renewal terms, and any trial or introductory offer. Premium benefits may include full detail views for saved items and related characters, system-following dark appearance, Dark and True black themes, ad-free use for covered placements, and other features expressly shown before purchase. A reference to possible or upcoming benefits is not a guarantee that any particular feature will be delivered.

• Apple or Google charges the platform account used to confirm the purchase and handles payment methods, taxes, billing records, price changes, refunds, and applicable purchase authentication.
• Monthly and annual subscriptions renew automatically at the price and interval shown by the store unless cancelled before the store's renewal deadline. Uninstalling KyouStudy does not cancel a subscription.
• Manage or cancel an Apple subscription in Apple subscription settings and a Google Play subscription in the Google Play subscription center. Cancellation ordinarily stops future renewal, while access continues through the paid period, subject to store rules and law.
• Eligible purchases can be restored through the app's Restore Purchases action on a platform account entitled to the product.
• A pending, expired, refunded, revoked, unacknowledged, upgraded, fraudulent, or unverified transaction may not provide or may cease to provide Premium access.
• Switching between monthly and annual plans, duplicate-purchase controls, proration, grace periods, billing retry, family sharing, offers, refunds, and regional availability are governed by store configuration and the applicable store.

"Lifetime" means access to the lifetime-purchase benefits supported by KyouStudy for as long as HungBok continues to make a compatible version of KyouStudy available; it does not mean your lifetime, guarantee perpetual operation, or require us to maintain obsolete devices, platforms, third-party services, or every individual feature forever. This sentence does not limit any non-waivable consumer right or store remedy.

We may improve, replace, add, or retire individual Premium features while maintaining meaningful paid value. We will not intentionally remove all paid benefit during an active paid subscription period without a remedy required by law or the applicable store. The Apple Standard EULA applies where Apple makes it part of your app license, and Google Play Terms apply to Google Play purchases.

10. Advertising and Analytics

The free tier displays Google AdMob banner advertisements in selected app screens. These may include fixed-size or adaptive banner placements sized for the available screen area. Current KyouStudy releases do not offer interstitial, native, or rewarded-ad placements. Premium users with a successfully resolved entitlement are not shown KyouStudy's covered banner placements, although purchase verification and previously recorded consent or measurement data may still be processed.

AdMob and its advertising partners select and deliver the advertisement. Depending on consent, age treatment, region, and platform settings, a banner may be personalized, non-personalized, contextual, or limited. Ads are visually identified and may open a third-party app or website when selected. HungBok does not choose or endorse every advertised product, is not the seller, and is not a party to a transaction with an advertiser.

KyouStudy uses Google Analytics for Firebase in the Android and iOS apps and Google Analytics through the Google tag on the website. These services measure automatically collected events and properties such as app or page opens, sessions, screen or page activity, engagement, app version, operating system, device category or model, language, approximate region, acquisition information, and technical performance. Google Analytics assigns pseudonymous app-instance, browser, cookie, or similar identifiers as applicable. We do not deliberately place exact studied expressions, answer contents, bookmarks, notification text, complete learning histories, names, or email addresses into Analytics events.

Google Mobile Ads may process IP-derived general location, app and ad interactions, ad requests, impressions and clicks, diagnostic and performance information, consent signals, and device or app-scoped identifiers, including an advertising identifier where the platform makes it available and applicable consent permits. Analytics and advertising information is used for service measurement, release quality, ad delivery, frequency control, reporting, security, and fraud prevention. Consent choices, iOS App Tracking Transparency, Android advertising controls, website controls, and regional opt-outs are described in the Privacy Policy.

You must not hide, overlap, repeatedly refresh, automate, or fraudulently create or encourage ad requests, impressions, installs, conversions, or clicks. Do not click banners to support KyouStudy or ask others to do so. We may limit ad-supported or network features to protect users, advertisers, and the integrity of the Services.

11. Website, Links, and Support Communications

The website provides product information, legal documents, contact channels, and licensing notices. You may link to public pages in a lawful way that does not falsely imply endorsement. Automated access must respect reasonable rate, security, and technical restrictions.

If you contact us, you authorize us to receive, reproduce, inspect, and use the message and attachments as reasonably necessary to respond, investigate a problem, protect the Services, or meet legal obligations. Do not send passwords, payment-card numbers, government identifiers, confidential exam questions, or unrelated sensitive information.

Third-party links are provided for convenience and may change. We are not responsible for the content, security, availability, or practices of a third-party site.

12. Third-Party Services

The Services may interact with Apple App Store, StoreKit, Apple Photos, Apple speech and notification services, Google Play, Google Play Billing, Android media, notifications and TTS engines, device backup systems, Cloudflare Workers and D1 for content reports, hosting and content-delivery providers, email services, account or sync providers, share destinations, Google Analytics for Firebase, the Google tag, Google AdMob, User Messaging Platform, and disclosed advertising partners.

Third-party services are operated by their owners and may require separate accounts, permissions, fees, terms, privacy notices, age rules, or regional eligibility. We do not control their availability, decisions, security, content, or data practices. Your dispute with Apple, Google, an advertiser, a TTS provider, a share destination, or another third party is governed by your agreement with that party, without limiting any responsibility HungBok cannot lawfully exclude.

13. Your Learning Records, Content Reports, Saved Images, and Feedback

As between you and HungBok, you retain rights you already hold in information you enter or generate through your study activity. The app's local progress records do not grant HungBok ownership of your personal study history.

If you voluntarily send feedback, a correction, or a suggestion, you grant HungBok a worldwide, perpetual, irrevocable, royalty-free, non-exclusive right to use, reproduce, adapt, and incorporate that feedback to operate and improve KyouStudy without an obligation to compensate you. This does not transfer ownership of personal information, which remains governed by the Privacy Policy.

A content-problem report contains a snapshot of KyouStudy material and technical context rather than a user-authored explanation. You authorize HungBok to inspect and use the report as reasonably necessary to reproduce, classify, correct, reject, or consolidate the issue and improve the affected content or feature.

You must have the right to share any exported image, attachment, or other material you send. Do not use KyouStudy to disclose another person's private information or copyrighted material without authorization.

14. Prohibited Use

You may not, and may not help another person to:

• copy, scrape, extract, modify, translate, publish, sell, rent, sublicense, redistribute, or create a competing dataset or service from KyouStudy or its content except as a separate open-source or content license expressly permits;
• download in bulk, isolate, reproduce, republish, redistribute, sell, license, adapt, or use KyouStudy's AI-generated or AI-assisted voices, audio, illustrations, or images to train, fine-tune, evaluate, or supply another machine-learning model, voice clone, image generator, dataset, media library, or commercial product without HungBok's prior written permission or another express legal authorization;
• reverse engineer, decompile, disassemble, discover source code, bypass encryption or access controls, or create derivative software except to the limited extent applicable law does not allow that restriction;
• circumvent Premium entitlements, purchase validation, content limits, ads, consent controls, rate limits, security, or technical restrictions;
• use bots, crawlers, automation, bulk requests, or other methods that burden, probe, test, interfere with, or damage the Services or another system;
• upload, transmit, distribute, or use content that is unlawful, fraudulent, deceptive, abusive, malicious, infringing, privacy-invasive, or designed to facilitate cheating on a live examination;
• impersonate HungBok, KyouStudy, an exam organization, another person, or falsely suggest affiliation, certification, sponsorship, or endorsement;
• introduce malware, exploit vulnerabilities, obtain unauthorized access, collect another person's information, or interfere with store, analytics, advertising, notification, or network integrity; or
• use the Services in violation of law, sanctions, export controls, school or exam rules, platform policies, or another person's rights.

15. KyouStudy Intellectual Property

Except for materials governed by separate licenses, the KyouStudy software, product design, user interface, original text, original translations and examples, graphics, app icons, website, databases, selection and arrangement of content, and KyouStudy and HungBok names and marks are owned by or licensed to HungBok and protected by intellectual-property and unfair-competition laws.

KyouStudy's voice, audio, illustration, and image assets may include AI-generated or AI-assisted material. To the extent recognized by applicable law, rights in original prompts, scripts, recordings, edits, curation, selection, coordination, arrangement, and other protectable elements are owned by or licensed to HungBok or the identified provider. Regardless of whether every individual machine-generated element independently qualifies for copyright protection in a particular country, your permission to access the Services does not grant a contractual license to extract, republish, redistribute, commercialize, clone, or use those assets for model training. Ordinary in-app viewing and a personal save or share action expressly enabled by KyouStudy remain permitted for their intended non-commercial purpose.

No right is granted except the limited license in Section 4. You may not use KyouStudy's name, icon, screenshots, visual identity, or trade dress in a way that suggests endorsement or affiliation without written permission. Rights not expressly granted are reserved.

16. Open-Source Software, Licensed Content, and Attributions

KyouStudy includes or is built with third-party software, data, fonts, audio, and artwork. Each component remains subject to its own license. Copyright notices, attribution requirements, source descriptions, disclaimer clauses, and share-alike obligations are preserved and are not replaced by these Terms.

The direct shipped software versions reflected by this notice are listed in the Open-Source Software Notice. Development-only tools and tests do not become part of the distributed app merely because they appear in the source repository.

Open-source and licensed components are generally provided by their authors without warranty, as stated in their licenses. Nothing in this section removes a warranty or remedy that applicable consumer law requires HungBok to provide.

17. Privacy

The Privacy Policy explains local storage, backups, remote image requests, content-problem reports, permissions, purchases, support, website storage, accounts or sync where offered, analytics, advertising, network processing, retention, and deletion. By requesting a connected feature or using an optional third-party service, you direct the information necessary for that feature to the relevant server or provider under the applicable privacy notice.

18. Availability, Updates, and Changes to the Services

We may release updates; change content, providers, limits, supported devices, courses, languages, or tiers; correct data; suspend a network or reporting feature; or discontinue all or part of the Services for security, legal, licensing, operational, or product reasons. We do not guarantee uninterrupted server communication or that every feature, report submission, image, voice, item, advertisement, analytics service, or purchase will be available, delivered, or processed at all times or in every region.

Where reasonably possible, we will provide notice of a material discontinuation or paid-feature change. We may act without advance notice when needed for security, legal compliance, rights protection, or a third-party service failure. Store obligations and mandatory consumer remedies continue to apply.

19. Disclaimers

To the maximum extent permitted by law, the Services are provided "as is" and "as available." HungBok disclaims implied warranties of merchantability, fitness for a particular purpose, accuracy, quiet enjoyment, and non-infringement where those disclaimers are legally permitted.

Without limiting the above, we do not warrant uninterrupted or error-free operation; complete or accurate study data, translations, pronunciations, stroke forms, images, reminders, statistics, or answers; successful backup, restore, cache, purchase, or entitlement processing; compatibility with every device; availability of a third-party service; or any learning or exam outcome. Some jurisdictions do not allow certain disclaimers, so part of this section may not apply to you.

20. Limitation of Liability

To the maximum extent permitted by law, HungBok will not be liable for indirect, incidental, special, consequential, exemplary, or punitive damages, or for loss of data, progress, opportunity, profits, revenue, goodwill, exam fees, or expected savings arising from or related to the Services or these Terms.

To the maximum extent permitted by law, HungBok's aggregate liability arising from or related to the Services or these Terms will not exceed the greater of (a) the amount you paid for KyouStudy through the applicable app store during the 12 months before the event giving rise to the claim or (b) USD 20. This limitation does not apply to fraud, willful misconduct, death or personal injury caused by negligence, breach of a non-waivable statutory duty, or any liability that applicable law does not allow us to limit.

21. Suspension and Termination

You may stop using the Services at any time and uninstall the app. You must separately cancel an auto-renewing subscription through Apple or Google; uninstalling does not cancel it. Before deleting app data, save anything you need and manage platform backups, photos, shared copies, and store records separately.

We may suspend or terminate access to a network, Premium, website, advertising, or other feature if you materially breach these Terms; create security, fraud, legal, licensing, or operational risk; or if the relevant service is discontinued. Provisions that by their nature should survive will survive, including payment obligations, ownership, license notices, feedback rights, disclaimers, liability limits, and general terms.

22. Changes to These Terms

We may revise these Terms when the Services, purchases, Premium benefits, content-reporting system, AI-assisted media, advertising, analytics, providers, licenses, platform requirements, or law change. We will post the revised Terms with a new date and provide additional notice when reasonably appropriate. Continued use after the effective date means acceptance only to the extent permitted by law. If express consent is required, we will request it separately.

23. Applicable Law and Disputes

These Terms are governed by the law applicable to the relationship between you and HungBok, without applying a rule that would select another jurisdiction's law. Nothing in these Terms deprives you of mandatory consumer protection, privacy rights, or a mandatory court or dispute forum available in your country or region. The United Nations Convention on Contracts for the International Sale of Goods does not apply.

Before filing a claim, please contact [email protected] and describe the issue so the parties can try to resolve it informally. This request does not shorten or waive a legal deadline or mandatory remedy.

24. General Terms

These Terms, the Privacy Policy, applicable open-source and content licenses, the Apple Standard EULA or Google Play terms where applicable, and terms presented in a purchase flow form the agreement governing the Services. If a provision is invalid or unenforceable, it will be enforced to the maximum lawful extent and the remaining provisions remain in effect. A failure to enforce a provision is not a waiver.

You may not assign these Terms except where law permits. HungBok may assign them in connection with a reorganization, financing, transfer of the Services, or business transaction, subject to applicable law and continued protection of your rights. Headings are for convenience. "Including" means "including without limitation." The English version is the only official version of these Terms.

25. Contact