Terms of service

Last updated October 18, 2026

By using Zero to Frontier you agree to these terms. If you do not agree, please do not use the site.

The book

Reading, running code, and exercises are free. The text and figures are licensed under CC BY-NC-SA 4.0, and the code under the MIT license, so you may share and adapt them non-commercially with credit.

AI plans and credits

  • The AI features (the tutor, coding help, Notes AI) and the Playground need a monthly plan. Each plan includes a number of credits every month. Each answer is metered by how much the model actually reads and writes, so a short answer costs less than a long one. A typical answer uses 1 to 6 credits depending on the model, and the picker shows each model's typical cost.
  • Plan credits reset when your plan renews and do not carry over. Top-up credits never expire.
  • Plans renew monthly until you cancel. You can cancel anytime from your Account page, and your plan stays active until the end of the period you paid for.
  • Payments are processed by Stripe and sold through its Link service, which also handles sales tax. Credits have no cash value and are not refundable, except where the law requires.
  • We may change prices for future periods. We will tell you before a change applies to your plan.

AI answers

AI answers can be wrong. Treat them as a study aid and check important claims against the book and its sources. Do not rely on them for professional, legal, medical, or financial decisions.

Fair use

Please do not abuse the service, attempt to break it, scrape it at scale, resell access, or use the AI features for anything unlawful. We may suspend accounts that do.

No warranty

The service is provided as it is, without warranties of any kind. To the extent the law allows, we are not liable for indirect or incidental damages, and our total liability is limited to what you paid us in the last three months.

Changes and contact

We may update these terms and will post the new date above. Questions can go through Contact us in the account menu, or to hello@zerotofrontier.app.