Terms of Service

Last updated: 01/06/2026

The short version

• There's a free tier (Auditor) and paid tiers (Scholar, Enrolled, Honors). On the free tier and on Scholar you bring your own AI provider key; the managed tiers include compute.
• Paid plans are billed monthly or annually and you can cancel anytime — access runs to the end of the period you paid for.
• Payments are processed by Lemon Squeezy, our reseller and merchant of record, who handles billing, receipts, and tax.
• Only upload materials you actually have the right to use for personal study.
• The tutor can be wrong. Don't take its answers as professional advice.

1. Who can use Professor Otto

To create an account, you need to be 18 or older, be legally capable of entering into a contract under applicable law, and not be barred from using services like this by applicable law or sanctions.

2. The service

Professor Otto is an AI tutor that reads your uploaded textbooks and syllabi and helps you study them. It's in active development — features may change, break, or be removed. We try not to surprise you with that, but we can't guarantee uptime or that every feature stays the same.

3. Your account

• One person per account. Don't share credentials.
• Keep your sign-in secure. Tell us promptly if you suspect it's been compromised.
• You're responsible for what happens under your account.

4. Plans, BYOK, and fees

Professor Otto offers a free tier and paid subscription tiers:

• Auditor (free). No charge from us. New accounts get a one-time welcome credit to finish a first course; after that you bring your own API key to keep using the free tier.
• Scholar (paid, bring your own key). A subscription fee to us for the surrounding product; you still bring your own API key or OAuth credential from Anthropic, OpenAI, or Google and pay that provider directly for model usage.
• Enrolled and Honors (paid, managed compute). A subscription fee that includes AI compute we provide for you — no key required.

For the bring-your-own-key tiers, your agreement for the AI model itself is with the provider. We're not responsible for their charges, rate limits, outages, or policy changes, and if you want a hard spending ceiling you can set a cap in your provider's dashboard. Billing, cancellation, and refunds for the subscription you pay us are covered in Section 5.

5. Billing, cancellation, and refunds

• Billing cycle. Paid plans are billed in advance on a recurring basis — monthly or annually, depending on the cycle you choose — and renew automatically until you cancel. Annual plans are billed once for the year.
• Cancellation. You can cancel anytime, yourself, through the customer portal provided by our merchant of record. Cancellation stops future renewals; it does not retroactively refund the current period.
• Access after cancellation. When you cancel a paid plan, you keep that plan's access until the end of the period you've already paid for. After that, your account moves to the free Auditor tier.
• Changing plans. You can upgrade or downgrade at any time; changes take effect as described at checkout (typically upgrades immediately, downgrades at the next renewal).
• Refunds. Except where required by applicable consumer law, subscription fees are non-refundable once a period has begun. If something has gone wrong, email support@professor.ac and we'll deal with it fairly.
• Taxes. Prices may be shown exclusive of tax. Any VAT, sales tax, or other applicable taxes are added and collected by our merchant of record according to your jurisdiction.
• Merchant of record. Payments are processed by Lemon Squeezy, our reseller and merchant of record, who handles the transaction, billing, receipts and invoices, and applicable tax on our behalf. Your purchase is also subject to their terms at checkout.
• Price changes. We may change subscription prices going forward. We'll give notice before a change affects you, and any new price applies from your next renewal — never retroactively to a period you've already paid for.

6. Content you upload

Professor Otto works by reading textbooks and syllabi you upload.

• Your rights. You represent that you either own the material you upload or otherwise have the right to use it for personal study on Professor Otto.
• License to us. You grant us a limited, non-exclusive, non-transferable license to store and process your uploads solely to provide Professor Otto to you — nothing more. We don't use your uploads to train models or build other products.
• Ownership. The materials remain yours. Deleting them from Professor Otto removes them from our systems as described in the Privacy Policy.

7. The tutor's output

The tutor generates explanations, answers, examples, and other output in response to you and your materials.

• Your use of output. As between you and us, you're free to use the tutor's output for your own personal study. We don't claim ownership of it.
• No warranty. Output is produced by third-party AI from your prompts and materials. It can be wrong, incomplete, or unsuitable — see the disclaimers in Section 13. Don't rely on it as fact or as professional advice.
• Similar output for others. AI can generate similar or identical output for different people. Nothing stops us or other users from producing comparable output, and you don't get any exclusive rights in what the tutor generates.

8. Copyright complaints

Professor Otto respects copyright. If you're a rights holder and believe content on Professor Otto infringes your rights, email support@professor.ac with:

• Your name and contact information
• A description of the copyrighted work
• Enough detail for us to identify the specific material on Professor Otto (e.g., the book title or user identifier if known)
• A statement that you have a good-faith belief the use isn't authorized
• Your signature (electronic is fine)

We'll review and, where appropriate, remove the material and notify the user who uploaded it. Accounts with repeat infringement issues will be terminated. This process is designed to align with applicable copyright law.

9. Acceptable use

Don't:

• Reverse-engineer, scrape, or interfere with Professor Otto beyond what's needed to use it normally.
• Use Professor Otto to violate your school's academic integrity policy. The product is designed to teach, not to do your work for you, but how you use it is on you.
• Upload unlawful content, malware, or material that infringes someone else's rights.
• Share your account or sell access to it.
• Use the service to harass or harm others, or to generate content that is illegal under applicable law.

10. Fair use of managed compute

On the managed tiers (Enrolled and Honors) we provide the AI compute, and on the free tier we provide a one-time welcome credit. That compute is meant for normal, personal study.

• We may set, and adjust, reasonable rate limits and fair-use thresholds on managed usage.
• We may throttle, suspend, or move to a bring-your-own-key arrangement any usage that is automated, resold, shared across multiple people, or far outside normal personal study.
• If usage looks abusive or your account looks compromised, we may pause it and contact you before restoring access.

This keeps the managed tiers sustainable and protects the service for everyone. Bring-your-own-key usage is billed by your provider rather than us, so these limits don't apply to it — your provider's limits do.

11. Our intellectual property

Professor Otto — the app, the brand, the interface, the code we wrote — is ours (or our licensors'). You get a personal, revocable, non-exclusive license to use it. You don't get any other rights, and "Professor Otto" is not yours to use as a brand.

12. Feedback

You're not required to send us feedback. But if you send us ideas, suggestions, or other feedback, you grant us a perpetual, irrevocable, royalty-free license to use it freely to improve Professor Otto — with no obligation, confidentiality, or compensation owed to you.

13. Disclaimers

• Professor Otto is provided "as is" and "as available." We don't promise it will meet every need, be uninterrupted, or be free of errors or bugs.
• AI answers can be wrong. The tutor is not a substitute for your professor, a licensed professional, or your own judgment. Treat everything it produces as a study aid, not as fact.
• Not professional advice. Nothing Professor Otto outputs is legal, medical, financial, psychological, or other professional advice, even when your textbook is on those topics.
• Provider output is not ours. We don't guarantee the accuracy, safety, or legality of content generated by Anthropic, OpenAI, Google, or any other third-party AI.
• Keep your own copies. Because the service is provided as available, data can be lost, corrupted, or deleted, and we're not liable for loss of your uploads, session history, or other data. Keep your own copies of anything important.

14. Limitation of liability

To the maximum extent permitted by applicable law:

• We are not liable for any indirect, incidental, consequential, special, or punitive damages arising from your use of Professor Otto — including lost grades, missed deadlines, wrong answers, or fees charged by your AI provider.
• Our total liability to you for direct damages is capped at the greater of 30 USD and the total amount you paid us for subscriptions in the 12 months before the claim.
• Nothing in these terms limits any liability we can't legally disclaim, including under the mandatory consumer protection law that applies to you.

15. Indemnification

You agree to indemnify and hold Professor Otto and its operator harmless from claims, damages, and reasonable legal fees arising from content you uploaded without having the right to upload it, or from your breach of these terms.

16. Termination

• You can stop using Professor Otto and delete your account at any time.
• We can suspend or terminate your account if you materially breach these terms, if continuing to provide the service becomes unlawful, or if we shut the service down.
• Sections that by their nature survive termination — disclaimers, limitation of liability, indemnification, governing law — survive.

17. Third-party services and their terms

Professor Otto runs on top of services we don't control. When you use it, you're also bound by their rules:

• AI providers (Anthropic, OpenAI, Google). Whether you bring your own key or use our managed compute, the AI model is operated by the provider. Your use of it is also governed by that provider's terms of service and usage / acceptable-use policies, and you agree not to use Professor Otto to do anything those policies prohibit. We're not responsible for a provider's decision to refuse, filter, or restrict output.
• Payments (Lemon Squeezy). Purchases are also subject to our merchant of record's terms presented at checkout, as described in Section 5.
• Sign-in (Clerk). Authentication is handled by Clerk and subject to their terms.

If a provider changes, restricts, or withdraws its service, we may have to change or withdraw the corresponding part of Professor Otto.

18. Export controls and sanctions

Professor Otto, and the AI providers behind it, are subject to export-control and economic-sanctions laws. By using the service you represent that:

• You are not located in, or a resident of, a country or region subject to comprehensive government sanctions.
• You are not on any government list of restricted or prohibited parties.
• You will not use Professor Otto where doing so would violate applicable export-control or sanctions law.

If any of this stops being true, you must stop using the service. We may block access where the law — or one of our providers — requires it.

19. Informal dispute resolution

If you have a problem, we'd rather fix it than fight about it. Before starting any formal legal action, email support@professor.ac describing the issue and what you'd like us to do, and give us 30 days to resolve it. Most things can be sorted out this way. This step doesn't apply where waiting would cause you to miss a deadline (a limitation period) for bringing a claim.

20. Governing law and venue

These terms are governed by the laws of the operator's principal place of business, without regard to conflict-of-laws rules. The competent courts of that jurisdiction have exclusive jurisdiction over any dispute arising from or related to these terms, except where the mandatory consumer law of your country of residence requires otherwise.

21. General

• Entire agreement. These terms and the Privacy Policy are the entire agreement between you and us about Professor Otto, and replace any earlier understanding on the subject.
• Severability. If any part of these terms is found unenforceable, the rest stays in force, and the unenforceable part is applied as closely as the law allows to its original intent.
• No waiver. If we don't enforce a part of these terms, that's not a waiver — we can still enforce it later.
• Assignment. You may not transfer your rights or obligations under these terms. We may transfer ours — for example, if Professor Otto is acquired or reorganized — and will let you know if that materially affects you.
• Force majeure. We're not liable for delays or failures caused by events beyond our reasonable control, including outages or changes at our infrastructure or AI providers, network failures, or acts of government.

22. Changes to these terms

We may update these terms as the product evolves. We'll post updates on this page and revise the "last updated" date. If the changes are material, we'll also surface them in the app. Continuing to use Professor Otto after changes take effect means you accept them — if you don't, stop using the service.

23. Contact

• Legal, Copyright, General: support@professor.ac

Operator: Professor Otto, an independently operated sole proprietorship. Contact: support@professor.ac.