Last updated: 15 September 2026
Duru is provided by Silvan Jost, an individual trading as Duru, not a company.
Contact: [email protected]
Duru turns material you provide into an ordered course: it extracts vocabulary and grammar, splits a long document into lessons, schedules review, generates practice, and provides an AI tutor you can talk to. The tutor can, when you ask it to, add words and patterns to your course.
Duru is a study tool. It is not a teacher, a tutor service, a qualification, or a substitute for instruction from a qualified person.
You need an account, created with an email address and password or through a sign-in provider such as Google. Keep your credentials secure; you are responsible for activity under your account. Tell us promptly if you believe it has been compromised.
You must be at least 16. Duru is not designed for children and has no parental-consent mechanism.
This is the most important section, because it is where the real risk sits.
You keep ownership of what you upload. We claim no rights in your material beyond what is needed to run the service for you.
You must have the right to upload it. By uploading, you confirm you own the material or are otherwise permitted to use it this way. Uploading a textbook you bought does not automatically give you the right to transmit it to a third-party AI provider — check the licence.
Uploaded material is sent to AI providers. Extracting vocabulary from a PDF means transmitting that PDF to OpenRouter, which routes it to a model provider; scanned pages are read by an OCR model the same way. What you say to the tutor is transmitted to Google. If you are not comfortable with a specific document leaving our servers, do not upload it. The privacy policy lists every provider.
You are responsible for what you share. If you share a course, you are responsible for having the right to distribute its contents to the people you share it with.
Copyright complaints. If you believe material in a shared course infringes your rights, write to [email protected] with a link to the course or the share link, a description of the material, and the basis of your claim. We will remove material on a credible complaint and may suspend accounts that repeatedly upload material they have no right to use.
The sample documents offered when you create your first course are built from sentences contributed to Tatoeba (tatoeba.org) under the Creative Commons Attribution 2.0 France licence. The attribution is printed in each document and in the course description. You may reuse those sentences under the same licence; the word lists, grammar notes and exercises Duru generates from them are AI output, as described in section 5.
Extractions, translations, example sentences, grammar explanations, test questions, corrections, tutor conversations, and words or patterns the tutor saves for you are generated by AI models. They will sometimes be wrong, including confidently wrong.
Free plan. The free plan is free and stays free. It comes with a monthly allowance of imported lessons and tutor minutes, shown in the app. Lessons you have already imported stay available to review without limit. We may change the size of the allowance; we will not start charging for it.
Paid plans are billed monthly, in advance, at the price shown at checkout. Each plan's allowance is shown in the app and resets with your billing period. No plan offers unlimited tutor time: every plan states the hours it includes, and a call that is left open with nobody speaking is ended automatically.
Payment is processed by Stripe. Where Stripe acts as the seller of record, Stripe issues the receipt, handles VAT or sales tax, and its own consumer terms apply to the payment. Card details go to Stripe and never reach us.
Starting immediately. A paid plan begins as soon as payment succeeds. By subscribing you ask us to start the service straight away and acknowledge that, where a statutory right of withdrawal exists for digital services, it ends when the service starts.
Cancelling. You can cancel at any time from Account → Manage subscription. You keep the plan until the end of the period you have paid for, and are not charged again. We do not refund the remainder of a period, except where the law or Stripe's consumer terms require it. Cancel before deleting your account: deleting the account does not by itself stop the subscription.
Price changes. We will tell you by email before a price change applies to your renewal, and you can cancel before it does.
Non-payment. If a renewal fails, the account returns to the free plan. Your courses and data stay; only the allowance changes.
Do not:
The AI providers we use have their own usage policies, which apply to what you send through Duru. In practice they forbid the same things this list does.
Duru is provided as-is, with no guarantee of uptime, and it depends on third-party AI providers whose availability we do not control. Features may change or be removed. We may need to take it down for maintenance. If we ever discontinue the service, we will give you notice and time to download your data.
How data is handled is described in the privacy policy, which forms part of these terms.
You can delete your material at any time. Deleting a course deletes its lessons, extractions, generated practice and review history. You can download everything we hold about you from Account → Download my data.
You can stop and delete your account at any time.
We may suspend or terminate accounts that breach these terms, that put the service at legal risk, or that make it impractical to operate. If we terminate a paid account for a reason other than a breach, we refund the unused part of the current period.
To the maximum extent the law allows, Duru is provided without warranties, and we are not liable for indirect or consequential loss, lost data, or loss arising from reliance on AI-generated content.
Nothing here limits liability that cannot legally be limited. If you are a consumer, nothing in these terms takes away rights you have under the law of the country where you live.
We may update these terms. Material changes will be communicated by email or in the app before they take effect, and continuing to use Duru after that date means you accept them.