Terms of Use

Last updated: August 25, 2026

By purchasing or downloading System Design Unboxed you agree to these terms.

1. What you're buying

System Design Unboxed is a digital product. A purchase gives you the full book as a PDF and EPUB, plus the accompanying diagram files in Mermaid, SVG and draw.io formats, delivered as an instant digital download.

2. License

• The book and files are licensed to you for personal, non-commercial use — read, print for your own use, and study them freely.
• You may use and modify the diagrams in your own notes, projects and interview preparation.
• You may not resell, redistribute, republish or share the book or the original files with anyone else (including uploading them to public repositories or file-sharing sites).

3. Payments

Payments are processed securely by Lemon Squeezy. The book is delivered as an instant digital download. If something goes wrong with your order — for example, your download link never arrives — contact us and we'll sort it out (see section 8).

4. No refunds

All sales are final. Because this is a digital product delivered instantly, we don't offer refunds once the download has been provided. If you experience a technical issue with your order, contact us and we'll make it right.

5. No physical copy

This book is digital only. A physical printed edition may come later, but a purchase here doesn't include one.

6. Intellectual property

The book, its text, diagrams and design are © 2026 LeXTrem Books. All rights reserved. Nothing in these terms transfers ownership of the content to you.

7. Disclaimer

The content is provided "as is" for educational purposes. It doesn't guarantee interview outcomes and isn't affiliated with any employer or interview process. We're not liable for any loss arising from its use.

8. Changes & contact

We may update these terms from time to time; the date at the top reflects the latest version. Questions about an order or these terms: info@lextrem.com.