Privacy Policy

Your account. You don't need an account for the free lessons. If you sign in, we keep your email address. Signing in with Google also gives us the name and profile picture on your Google account. Sign-in happens through a one-time email link or Google, so we never have a password for you.

Billing. When you subscribe to Pro, you pay on a checkout page run by Stripe. Your card details go to Stripe and never reach our servers. Stripe tells us your customer and subscription IDs, whether the subscription is active, and when it renews or ends, and we keep those so we know which lessons to unlock.

GitHub, if you connect it. Connecting GitHub gives us your GitHub username and an access token that can create and write to public repositories. We store the token encrypted and use it only when you press Save to GitHub.

Code you compile. Python runs entirely in your browser. C++ and Rust have to be compiled first, so when you run a C++ or Rust program, its source goes to our compiler service. See Your code and progress.

Usage and technical data. Like most websites, our servers see your IP address, browser and the pages you request, and our hosting provider keeps short-lived logs of them. We also count page views with Vercel Web Analytics (see Cookies and local storage).

The code you write, the steps you've completed and the language you last picked are saved in your browser's local storage, on your device. They aren't sent to us or tied to your account, even when you're signed in. They stay in that browser only: clearing its site data erases them, and they don't follow you to another device.

When you run C++ or Rust, the program is sent to our compiler service, written to a temporary folder, compiled to WebAssembly and sent back. The folder is deleted straight after. The service keeps recently compiled programs in memory for a while so that running the same code again is instant; that copy isn't linked to you or your account. Its logs record the language, whether compiling succeeded and how long it took, never the code.

Save to GitHub publishes your code. It creates a public repository called crackrobotics-solutions in your GitHub account and commits your code there, where anyone can read it. Don't put anything private in code you save.

We use what we collect to:

• sign you in and keep you signed in;
• take payment, unlock Pro and show your plan on your account page;
• save your code to GitHub when you ask us to;
• compile and run your C++ and Rust programs;
• keep the site secure and working, and find and stop abuse;
• see which pages are used, in aggregate, so we know what to improve;
• email you about your account, such as sign-in links. We don't send marketing email from the site.

We don't sell your personal information, share it for advertising, or show ads. Our newsletter lives on Substack and you join it there, separately from your account.

We share data only with the services that run the site, each for its own job:

• Supabase runs sign-in and our database, and sends sign-in emails.
• Stripe processes payments and manages subscriptions and invoices.
• Vercel hosts the site and provides its page-view analytics.
• Google, if you sign in with Google, and GitHub, if you connect it. Each sees that you're connecting to CrackRobotics.
• jsDelivr, a content delivery network, serves the Python runtime (Pyodide) that lessons load, so it sees your IP address when you open one.
• Our compiler host runs the service that compiles C++ and Rust.

Each of these has its own privacy policy. We may also disclose information when the law requires it, to protect people's safety or our rights, or as part of a merger or sale of the business, in which case this policy continues to apply to it.

We use only what the site needs to work:

• Sign-in cookies keep you signed in.
• A GitHub cookie lasts ten minutes while you connect GitHub, to check that the reply really came from GitHub.
• Local storage holds your code, progress, language and light or dark theme on your device.

Vercel Web Analytics counts visits without cookies and without following you to other sites. It records the page, the site you came from, and your country, browser, operating system and device type, and tells repeat views apart with a short-lived identifier that isn't kept past the day. Stripe's checkout and billing pages set their own cookies, under Stripe's policy.

We keep your account details for as long as you have an account. If you disconnect GitHub from your account page, we revoke our access on GitHub and delete the token straight away; the repository and the code in it stay in your GitHub account, and are yours to keep or delete.

If you ask us to delete your account, we delete your account details and GitHub connection. Stripe keeps records of past payments for as long as tax and accounting law require. Server logs are kept for a short time and then deleted.

You can use the free lessons without an account, cancel Pro from your account page at any time, and disconnect GitHub whenever you like. Clearing your browser's data for this site removes your locally saved code and progress.

Wherever you live, you can ask us for a copy of the personal information we hold about you, or ask us to correct or delete it. Email support@crackrobotics.com from the address on your account and we'll respond within 30 days. Depending on where you live, you may also have the right to object to or restrict how we use your information and to complain to your local data protection authority.

The site is served only over HTTPS. Database access is limited so each account can read only its own rows, and GitHub tokens are stored encrypted with AES-256-GCM. No system is perfectly secure, though, so we can't promise that information will never be exposed. If you find a vulnerability, please tell us at support@crackrobotics.com.

We and our service providers are based in, or process data in, the United States and other countries. Wherever it is processed, we protect it as this policy describes.

CrackRobotics isn't meant for children under 13, and we don't knowingly collect personal information from them. If you believe a child under 13 has given us their information, email support@crackrobotics.com and we'll delete it.

When this policy changes, we'll update the date at the top. If a change is significant, we'll also tell you on the site or by email before it takes effect.

For questions about this policy or your data, email support@crackrobotics.com.