Terms of Service

1. Scope and Operator

These Terms of Service apply to the use of the language learning platform Langsi, accessible at www.langsi.app, and all associated mobile apps and services.

2. Description of Services

Langsi is a web-based SaaS language learning platform offering:

• AI-powered vocabulary learning with spaced repetition (Leitner method)
• Multilingual learning modes (flashcards, multiple choice, listening)
• Daily learning sessions with personalized goals and streaks
• AI-generated example sentences, explanations and coaching messages
• Text-to-speech pronunciation for vocabulary and example sentences
• Topic-based audio trainers and exercises
• Progress statistics and learning analytics

The available feature set depends on the user's selected plan.

3. Registration and User Account

Registration with a valid email address and password, or via Google OAuth, is required to use Langsi. The user affirms that the information provided at registration is truthful. The user account is non-transferable. The user is obliged to keep access credentials confidential and notify the operator immediately of any suspected misuse. Users must be at least 16 years old. Minors under 16 may only use Langsi with the consent of a parent or guardian.

4. Free Services (Free Plan)

Langsi offers a free basic access including:

• Access to one selectable language
• Daily learning goal of up to 40 vocabulary items per day
• All basic learning modes (flashcards, multiple choice, listening)
• Learning streak and progress statistics

The operator reserves the right to adjust the free scope at any time. Existing free plan users will be notified at least 14 days in advance of material restrictions.

5. Paid Services (Premium Subscriptions)

Langsi offers the following paid plans:

Current prices are displayed on the Langsi pricing page and apply from the time of contract conclusion.

7. Subscriptions and Contract Terms

Subscriptions are billed on a monthly or annual basis. The subscription automatically renews for the selected billing period unless cancelled in time. Cancellation: The subscription can be cancelled at any time at the end of the current billing period via: Profile > Subscription > Manage Subscription > Cancel, or by email to: info@data-informed-decisions.com. After cancellation, access remains until the end of the paid period.

8. Payment Processing (Stripe)

Payment processing is handled by Stripe (Stripe, Inc. / Stripe Payments Europe, Ltd.). Accepted payment methods: Credit card (Visa, Mastercard, American Express), SEPA direct debit (subject to availability), and other Stripe-supported methods. On failed payment, Langsi reserves the right to temporarily restrict access to paid features until the outstanding amount is settled.

9. Right of Withdrawal and Refunds

Right of withdrawal for consumers (EU): Consumers resident in the EU generally have a 14-day right of withdrawal from the date of contract conclusion for digital services. The right of withdrawal expires if the user expressly agrees that the service is provided in full before the withdrawal period expires and confirms the loss of the right of withdrawal. This consent is obtained during the purchase process.

Voluntary refunds: Outside the statutory right of withdrawal, refunds may be granted on a case-by-case basis at equitable discretion. Inquiries to: info@data-informed-decisions.com

12. Limitation of Liability

The operator is liable without limitation for damages arising from injury to life, body or health, and for intent and gross negligence. For ordinary negligence, the operator is only liable for breach of essential contractual obligations (cardinal obligations), limited to foreseeable, contract-typical damage. Further liability is excluded. In particular, the operator accepts no liability for: the accuracy, completeness or timeliness of AI-generated vocabulary and translations; the user's learning success; data loss caused by the user themselves; damages by third-party providers (Stripe, Google, Resend etc.) outside our sphere of influence.

16. Governing Law and Jurisdiction

The law of the State of Florida, USA, applies, excluding the UN Convention on Contracts for the International Sale of Goods (CISG). For consumers with habitual residence in the EU, the mandatory consumer protection provisions of their country of residence take precedence; in that case, the consumer's place of residence is the place of jurisdiction. For all other disputes: place of jurisdiction is Fort Lauderdale, FL, USA. EU ODR platform: ec.europa.eu/consumers/odr. We are not willing or obliged to participate in consumer arbitration proceedings.

ec.europa.eu/consumers/odr

17. Severability Clause

Should individual provisions of these Terms of Service be or become invalid or unenforceable, this shall not affect the validity of the remaining provisions. The invalid provision shall be replaced by a provision that comes closest to the economic purpose of the invalid provision.