Terms
Last updated 5 October 2026.
Using the site
- System Design Sim is free to use for learning, interview practice and teaching. No account is needed.
- Don't attack, overload or scrape the site, and don't use it to break the law.
- Embedding our simulations with the provided embed code is welcome, as long as the link back stays in place.
The numbers are estimates
- The simulator is a deliberately simple model. Capacities are rules of thumb and AWS prices were read once in October 2026; real systems and current prices differ.
- Don't make production, purchasing or budget decisions from these numbers alone. Load-test your own system and check the AWS pricing pages.
- The site is provided as is, without warranty. We are not liable for losses from using it or relying on it.
Content
- Guides, challenges, text and images on this site belong to System Design Sim. You may quote short parts with a link back.
- Designs you build and share are yours.
Changes and contact
- We may change these terms; the date above shows the latest version.
- Questions: hello@systemdesignsim.com.