Terms

Terms of use

Last updated 30 September 2026

1. 01The service

   HLD Lab helps you learn system design: lessons, a traffic simulator and a diagram editor. It is free to use. If we ever add paid features, we will say so clearly before charging anything.

   Features change as the product grows. Some, such as the AI assistant and passkeys, are early and may change or stop working without notice.

2. 02Your account

   • Use your own email address and keep your password and devices secure. One account per person.
   • You are responsible for what happens in your account. Tell us if you think someone else has access.
   • You can delete your account at any time from your profile.

3. 03Your work is yours

   You own the diagrams, answers and descriptions you create. You give us only the permission needed to store them and show them back to you while you use the service.

   Only put in what you have the right to. In particular, do not upload an employer's or client's confidential architecture unless you are allowed to share it with services like this one.

4. 04The AI assistant and other providers

   The assistant runs on your own API key with a provider you choose. Your use of that provider, including what it charges you, is between you and it, under its terms.

   AI output can be wrong or incomplete. Review a generated diagram before you rely on it.

5. 05Lessons and simulations

   Lessons are for learning. Scenarios inspired by real companies are practice exercises, not descriptions of how those companies actually build their systems. Simulations are simplified models, not benchmarks, and their numbers are illustrative.

6. 06Acceptable use

   Do not use HLD Lab to:

   • break the law or infringe anyone's rights;
   • attack, probe or overload the service, or try to reach other people's data;
   • create accounts automatically, or scrape the service at scale;
   • share diagrams containing spam, scams, malware links, or content that is illegal or harasses anyone.

   We may suspend or remove accounts that do, and remove diagrams that break these rules.

   To report a shared diagram, use Report on the diagram or write to hldlab.contact@gmail.com.

7. 07Availability and backups

   We work to keep HLD Lab running and your data safe, but we cannot promise it will always be available or that nothing is ever lost. Export diagrams you care about from your profile, and download lesson checkpoints you want to keep.

8. 08No warranty

   HLD Lab is provided as it is, without warranties of any kind, including fitness for a particular purpose or that it is free of errors.

9. 09Limitation of liability

   To the extent the law allows, we are not liable for indirect or consequential losses, lost data, or lost profits arising from your use of HLD Lab. Because the service is free, our total liability to you is limited to the amount you have paid us, which is nothing.

10. 10Ending

    You may stop using HLD Lab and delete your account whenever you like. If we ever shut the service down, we will give reasonable notice where we can, so you can export your work.

11. 11Changes and governing law

    When these terms change we update the date above; continuing to use HLD Lab after that means you accept them. These terms are governed by the laws of India.

Questions? Write to hldlab.contact@gmail.com.