Terms of Service

These terms are an agreement between you and CrackRobotics (“we”, “us”) covering your use of CrackRobotics, including its lessons, problems, simulator and subscriptions. By using the site you agree to them and to our Privacy Policy. If you don't agree, please don't use the site.

You must be at least 13 to use CrackRobotics. If you're under 18, a parent or guardian must agree to these terms for you and must make any purchase. If you use CrackRobotics for an organisation, you agree to these terms for it too.

CrackRobotics teaches robotics through programming exercises that run a physics simulation in your browser. The Pick & Place lesson and the first step of every other lesson are free, with no account needed. CrackRobotics Pro unlocks the rest.

We keep adding and improving lessons, so we may change, add or remove features and content over time. If we ever stop offering Pro, we'll give subscribers notice and refund any time they've paid for but not yet had.

You sign in with a one-time link sent to your email or with Google, so whoever controls your email or Google account can get into your CrackRobotics account. Keep those secure, and tell us at support@crackrobotics.com if you think someone else has used your account. An account is for one person; don't share it. You can stop using CrackRobotics at any time, and ask us to delete your account by emailing us.

• Price. Pro costs the monthly price shown on the pricing page when you subscribe, currently US$39, plus any tax that applies where you live. Stripe processes the payment.
• Renewal. Your subscription renews automatically each month, and we charge the card on file at the start of each month, until you cancel.
• Cancelling. You can cancel at any time from your account page. Pro stays on until the end of the month you've paid for and doesn't renew after that.
• Refunds. Payments aren't refundable, and we don't refund part-months, except where the law requires it or these terms say otherwise. If something went wrong with a charge, email support@crackrobotics.com and we'll put it right.
• Failed payments. If a payment fails, Stripe retries it and you keep Pro in the meantime. If it still can't be collected, the subscription ends.
• Price changes. If the price changes, we'll tell you at least 30 days before it applies to you. It takes effect at your next renewal after that, and you can cancel before then.

The code you write is yours. You give us only the permission we need to run the service: compiling your C++ and Rust on our servers, and committing your code to GitHub when you press Save to GitHub. We don't claim any other rights to it.

Save to GitHub publishes your code. It goes to a public repository in your GitHub account, where anyone can read it, and you're responsible for what you publish. You're welcome to share your own solutions this way. Your use of GitHub is governed by GitHub's terms.

The lessons, problems, instructions, starter code, grading checks, simulated scenes, diagrams and the rest of the site belong to us or to the people we license them from. While you follow these terms, we give you a personal, non-transferable licence to use them to learn.

Please don't copy, republish, sell or build a competing course from our lesson material, or get around the lock on Pro content. The site includes open-source software, such as MuJoCo and Pyodide, which remains under its own licences.

When you use CrackRobotics, don't:

• send code to our compiler that tries to read files, reach other systems, escape its sandbox, or use it for anything but the lessons;
• overload the site or the compiler, or scrape or download content in bulk with automated tools;
• probe, break or get around our security, sign-in or payment checks;
• share your account, or resell or give away access to Pro;
• use the site to break the law or to harm anyone.

If you find a security problem, please report it to support@crackrobotics.com rather than exploiting it.

CrackRobotics is for learning. Its simulations approximate real physics and leave a lot out, and code that passes every check here may behave very differently on real hardware. Don't rely on anything from CrackRobotics to control a real robot or any system where a failure could hurt someone or damage property without your own independent engineering, testing and safety measures.

CrackRobotics works with services run by others, including Stripe for payments, Google for sign-in, GitHub for saving code and Substack for our blog. Their own terms govern your use of them, and we aren't responsible for them. Links to papers and other sites are there for your reference; we don't control those sites.

We work hard to keep CrackRobotics accurate and available, but we provide it “as is” and “as available”. To the fullest extent the law allows, we make no warranties, express or implied, including that the site will be uninterrupted or error-free, that lesson content is complete or correct, or that it's fit for a particular purpose. Some places don't allow these exclusions, so they may not all apply to you.

To the fullest extent the law allows, we aren't liable for any indirect, incidental, special, consequential or punitive damages, or for lost profits, data or goodwill, arising from your use of CrackRobotics. Our total liability for any claim about CrackRobotics is limited to the greater of what you paid us in the 12 months before the claim and US$50. Nothing in these terms limits liability that the law doesn't allow us to limit.

We may suspend or close an account that breaks these terms, puts the service or other people at risk, or where the law requires us to. Where it's reasonable, we'll tell you first and give you a chance to fix the problem. If we close your account without you having broken these terms, we'll refund the unused part of any Pro month you've paid for. The sections on your code, our content, disclaimers and liability continue to apply after your account ends.

We may update these terms as CrackRobotics changes. We'll update the date at the top, and if a change is significant, we'll tell you on the site or by email before it takes effect. If you keep using CrackRobotics after that, you accept the new terms; if you don't, you can cancel Pro and stop using the site.

The laws of [state], United States govern these terms, without regard to conflict-of-law rules. If you're a consumer, you also keep the protections of the laws where you live, and you can bring a claim in your local courts. If any part of these terms can't be enforced, the rest still applies.

Questions about these terms? Email support@crackrobotics.com.