Terms of Service

    Katasaga
    Effective date: 12 September 2026
    Last updated: 12 September 2026

    These Terms of Service govern access to and use of the Katasaga website, web application, iOS application, live voice features, interactive stories, flashcards, and related services.

    1. Contracting party and contact details

    Katasaga
    KVK number: 42159778
    Website: https://katasaga.com
    Privacy and legal contact: dev@katasaga.com

    Katasaga is operated as a Dutch sole proprietorship registered with the Netherlands Chamber of Commerce. Registered business details are available through the Dutch Business Register.

    In these Terms, “Katasaga,” “we,” “us,” and “our” refer to the business identified above. “You” and “your” refer to the individual using the Service. The Katasaga website, application, and related features are collectively referred to as the “Service.”

    By creating an account, accessing the Service, or purchasing a subscription, you enter into a contract with Katasaga and agree to these Terms. If you do not agree, do not access or use the Service.

    2. Eligibility and age attestation

    The Service is available only to individuals aged 16 or older. During registration, you must affirmatively select the following statement:

    I confirm that I am 16 years of age or older.

    You must provide accurate information and must not create or use an account for an individual who does not satisfy this requirement. Katasaga does not currently offer a parental-consent pathway for younger users. If we reasonably believe that an account is being used by someone under 16, we may restrict or terminate access and delete associated data in accordance with the Privacy Policy.

    3. Description and purpose of the Service

    Katasaga is a language-learning service designed to help users practise languages through interactive stories, written exercises, flashcards, and artificial-intelligence-assisted text and voice conversations.

    Katasaga is not an accredited educational institution, examination provider, official CEFR certification service, tutoring service, medical service, legal service, financial service, crisis service, or emergency service. A level estimate or learning score generated by Katasaga is an informal product feature and is not an officially recognized qualification or assessment.

    4. AI features and limitations

    Katasaga uses automated systems to process speech, generate conversational responses, provide feedback, summarize sessions, estimate a user's starting level, judge scenario criteria, and screen for prohibited or unsafe content.

    AI output is generated automatically and is not reviewed by a human before delivery. It may be inaccurate, incomplete, biased, inappropriate, unavailable, or unsuitable for a particular user or situation. You must independently evaluate AI output and must not rely on it for medical, legal, financial, safety, mental-health, educational-certification, or other professional decisions.

    Katasaga does not guarantee that AI responses will be accurate, safe, complete, or appropriate; that conversations will be available without interruption; that a placement estimate corresponds to an official CEFR level; or that you will reach a particular proficiency level or examination result.

    If you face an emergency or safety-critical situation, contact the appropriate emergency or professional service rather than relying on Katasaga.

    5. Account registration and security

    You must provide accurate and current information when creating an account. Authentication is provided through Supabase Auth. You are responsible for maintaining the confidentiality of your credentials and for activity conducted through your account, except to the extent caused by Katasaga's failure to apply reasonable security measures.

    You must notify dev@katasaga.com promptly if you suspect unauthorized access. Katasaga may require account verification, password reset, or other security measures.

    You may delete your account through the account controls in Settings. Deletion is subject to the retention and legal-exception rules described in the Privacy Policy.

    6. Acceptable use and prohibited conduct

    You may use the Service only for lawful language-learning purposes. You must not use the Service, or encourage another person to use it, to:

    1. Request, create, transmit, distribute, or store sexually explicit, sexually exploitative, or sexually abusive content, particularly content involving minors.
    2. Harass, threaten, stalk, intimidate, bully, target, or abuse an individual or group.
    3. Create, promote, or distribute racist, sexist, hateful, discriminatory, dehumanizing, or extremist content.
    4. Encourage, facilitate, glorify, or instruct violence, self-harm, suicide, terrorism, abuse, exploitation, or other unlawful conduct.
    5. Submit content intended to make the Service produce harmful, illegal, sexual, hateful, or otherwise prohibited output.
    6. Attempt to bypass, disable, evade, manipulate, or interfere with safety controls, moderation, usage limits, subscription controls, or scenario grading, including through prompt injection, jailbreaks, or instruction-hierarchy attacks.
    7. Attempt to obtain system prompts, confidential instructions, credentials, API keys, security mechanisms, or other non-public information.
    8. Impersonate another person, misrepresent affiliation, infringe intellectual-property or privacy rights, or facilitate fraud.
    9. Upload malware or malicious code, disrupt the Service, probe or attack infrastructure, or access another user's account or data without authorization.
    10. Scrape, systematically extract, copy, reverse-engineer, resell, sublicense, or commercially exploit the Service or its content without written permission.
    11. Use the Service for spam, unsolicited marketing, harassment campaigns, or interference with another user's access.

    This section sets minimum requirements and does not limit Katasaga's ability to restrict conduct that is unlawful, unsafe, abusive, or materially harmful to users, providers, or the Service.

    7. Safety systems, moderation, and reports

    Katasaga uses automated safety controls that may analyze live conversation turns for harmful content, sexual or NSFW content, threats or hateful content, targeted abuse, prompt injection, and attempts to manipulate scenario grading. A session may be automatically ended when a safety control is triggered.

    Automated controls can make mistakes and may not detect every harmful or inappropriate output. If a conversation becomes inappropriate or unsafe, stop the session. To report a serious problem or request review of an account or moderation action, contact dev@katasaga.com with relevant details.

    Katasaga may introduce additional reporting, moderation, blocking, or appeal features in the future.

    8. User submissions and licence to operate the Service

    You retain rights you already hold in text, speech-derived text, or other material you submit to the Service. You grant Katasaga a non-exclusive, worldwide, royalty-free licence, limited to the period and purposes necessary to operate the Service, to host, transmit, convert, analyze, moderate, store, display to you, and process that material to provide the requested features.

    This licence allows Katasaga and its service providers to process input so that the Service can transcribe speech, generate responses, create summaries, evaluate scenarios, provide flashcards, enforce safety rules, and maintain account functionality. Katasaga does not claim ownership of your personal conversation content.

    You represent that you have the rights required to submit material and that your submissions do not violate law or another person's rights.

    9. Intellectual property

    The Service and its components—including software, stories, characters, artwork, audio, text, design, interfaces, trademarks, logos, and other materials—are owned by Katasaga or its licensors. Except for the limited licence expressly granted in these Terms, no rights are transferred to you.

    Subject to compliance with these Terms, Katasaga grants you a personal, limited, non-exclusive, non-transferable, non-sublicensable, revocable licence to access and use the Service for your own language learning. You may not copy, redistribute, publicly perform, sell, or create derivative works from Katasaga content unless permitted by law or written permission.

    10. Subscriptions, plans, and pricing

    Katasaga may offer free features and paid subscription plans. The applicable features, price, currency, billing interval, trial period, usage limits, taxes, and renewal terms will be displayed before purchase.

    10.1 Apple purchases

    Subscriptions purchased through the iOS application are processed through Apple's In-App Purchase system. Apple controls the payment transaction, subscription management, cancellation process, renewal notices, price-change notices, and refund process under Apple's applicable terms and policies.

    Manage or cancel an Apple subscription through the subscription settings associated with your Apple ID. Katasaga may receive subscription-entitlement information needed to provide paid features but does not receive your full payment-card number through Apple's In-App Purchase system.

    10.2 Web purchases

    When web subscriptions are available, payment is processed through Stripe Checkout or another Stripe-hosted payment interface. Katasaga does not receive or store your full payment-card number. Stripe may process billing, fraud-prevention, customer, transaction, and subscription information as described in the Privacy Policy.

    11. Trials, automatic renewal, and notices

    If you start a trial, the trial terms and the date on which it converts to a paid subscription will be shown before activation. Unless cancelled before the end of the applicable billing period or trial, an auto-renewing subscription renews for the same billing period at the then-current price, subject to applicable law and the rules of the purchase platform.

    Before purchase, we will present the price, billing interval, trial period, automatic-renewal condition, cancellation method, applicable taxes where required, and material usage limits.

    Katasaga will provide renewal-related information or reminders where required by law and where Katasaga controls the applicable billing channel. For Apple purchases, Apple manages applicable renewal notices, price-change notices, cancellation, billing, and refunds. For web purchases, Katasaga or Stripe may send transactional notices concerning upcoming renewals, payment status, failed payments, and price changes.

    You can cancel at any time through the platform used for purchase. Cancellation normally prevents the next renewal but does not automatically refund the current billing period, subject to mandatory statutory rights and the applicable platform's policies.

    12. Withdrawal, conformity, refunds, and consumer rights

    Nothing in these Terms removes a mandatory right available under applicable consumer law, including rights relating to withdrawal, conformity of digital content or services, defective performance, cancellation, or refunds.

    For purchases made through Apple, refund requests should generally be submitted through Apple's refund process. For purchases made through the web, contact dev@katasaga.com or use the refund and cancellation method presented at checkout.

    Where applicable law provides a withdrawal period for a digital service, Katasaga will provide the legally required pre-contract information and request any express consent necessary for the Service to begin immediately. If the law permits the withdrawal right to end or be adjusted after performance begins, Katasaga will apply the applicable statutory rules.

    13. Fair use and usage limits

    Live voice practice and other features may be subject to usage limits displayed in the applicable plan. Limits are intended to maintain reliability, prevent abuse, and keep the Service sustainable. Katasaga may adjust limits prospectively with reasonable notice where required.

    You must not bypass, share, manipulate, or abuse a usage limit or access-control mechanism.

    14. Fees and taxes

    Prices are displayed through the applicable purchase platform. Taxes may be included or added as required by law. A purchase platform may charge or collect taxes and fees according to its own terms.

    15. Suspension and termination

    Katasaga may suspend, restrict, or permanently terminate access where Katasaga reasonably believes that you:

    • Breached these Terms or another applicable policy.
    • Engaged in unlawful, abusive, hateful, harassing, sexual, exploitative, threatening, or unsafe conduct.
    • Attempted to evade safety controls, access controls, usage limits, or subscription restrictions.
    • Compromised or threatened the security, integrity, or availability of the Service.
    • Failed to pay an amount due.
    • Created a material risk to another person, Katasaga, or a service provider.

    For serious or urgent conduct—such as sexual exploitation, credible threats, hateful harassment, illegal activity, credential abuse, or attacks on the Service—Katasaga may act immediately without advance notice. Where reasonably practicable, Katasaga may provide an explanation and an opportunity to contact Katasaga regarding the action.

    Termination for a material breach by you does not create an automatic right to a refund for a period during which the Service was available to you. This does not exclude or limit mandatory statutory refunds, rights arising from Katasaga's breach or non-conforming performance, or Apple or Stripe refund rules.

    16. Availability and modifications

    Katasaga may modify, update, suspend, replace, or discontinue features, content, plans, providers, or parts of the Service. Katasaga will provide reasonable notice of material changes where required by law or reasonably practicable.

    Katasaga does not guarantee that the Service will always be available, uninterrupted, secure, error-free, compatible with every device, or free of harmful or inaccurate AI output.

    17. Disclaimers

    To the maximum extent permitted by law, the Service is provided “as is” and “as available.” Katasaga excludes warranties and conditions that may lawfully be excluded, including implied warranties of merchantability, fitness for a particular purpose, accuracy, uninterrupted availability, and non-infringement.

    Nothing in this Section excludes a statutory guarantee, mandatory consumer right, or liability that cannot lawfully be excluded.

    18. Liability

    To the maximum extent permitted by applicable law, Katasaga's aggregate liability for claims arising out of or relating to the Service is limited to the lower of:

    1. The total amount paid by you to Katasaga for the Service during the 12 months preceding the event giving rise to the claim; or
    2. EUR 100.

    To the maximum extent permitted by law, Katasaga is not liable for indirect, incidental, special, consequential, exemplary, or punitive loss, or for lost profit, lost opportunity, loss of goodwill, or loss of data, except where such limitation is not permitted by applicable law.

    Nothing in these Terms excludes or limits liability that cannot legally be excluded or limited, including liability for death or personal injury caused by negligence, fraud, intent, gross negligence, or other mandatory liability. If you have paid nothing, the first amount in the cap is zero; this does not limit liability that mandatory law protects.

    If you are a consumer in the European Union, mandatory consumer-protection rights in your country of residence remain unaffected.

    19. Indemnification

    To the maximum extent permitted by law, you agree to reimburse Katasaga for reasonable losses and costs arising from your material breach of these Terms, unlawful use of the Service, or infringement of another person's rights. This obligation does not apply to the extent a claim was caused by Katasaga's own negligence, unlawful conduct, or breach.

    20. Governing law and disputes

    These Terms are governed by the laws of the Netherlands. If you are an EU consumer, you retain the right to bring proceedings in the courts of your country of residence and retain all mandatory consumer-protection rights available there. Nothing in this Section prevents you from contacting a competent consumer authority.

    21. Changes to these Terms

    Katasaga may update these Terms when the Service, pricing, providers, or applicable law changes. Katasaga will publish the updated version with a new effective date and provide reasonable notice of material changes through the Service, website, or email where appropriate. Where applicable law requires express acceptance, Katasaga will request it.

    22. Contact

    Katasaga
    KVK number: 42159778
    Website: https://katasaga.com
    Privacy and legal contact: dev@katasaga.com