Terms of Service

Fair Terms, Plain English

Last Updated: January 11, 2026

The Bottom Line

✅ You CAN:

  • Play unlimited free Sudoku puzzles
  • Share puzzles with friends and classrooms
  • Download your progress data anytime
  • Use our content for personal and educational purposes
  • Cancel or delete your account anytime

❌ You CANNOT:

  • Copy our puzzles for commercial resale
  • Use automated bots to scrape content
  • Hack, abuse, or disrupt our services
  • Impersonate others or share false information
  • Violate any applicable laws

In short: Be respectful, play fair, and enjoy Sudoku. If you have questions about what's allowed, just ask us.

1. Agreement to Terms

Welcome to Sudoku Evil ("we," "us," "our"). By accessing or using our website at sudokuevil.io (the "Site") and related services (collectively, the "Service"), you agree to be bound by these Terms of Service ("Terms").

If you do not agree to these Terms, do not use our Service. Your continued use of the Service constitutes acceptance of these Terms and any future modifications.

Who Can Use Our Service

  • You must be at least 13 years old to use our Service independently
  • Users under 13 may use the Service with parental or guardian supervision
  • Teachers may create accounts on behalf of students for educational purposes
  • You must provide accurate information if you create an account
  • You are responsible for maintaining the confidentiality of your account

2. Acceptable Use Policy

You agree to use our Service in a manner that is lawful, respectful, and consistent with these Terms.

Permitted Uses

  • Personal entertainment and brain training
  • Educational purposes in classrooms and workshops
  • Sharing puzzles via our built-in share features
  • Printing puzzles for personal or classroom use
  • Cognitive therapy and rehabilitation (with supervision)
  • Friendly competitions and practice sessions

Prohibited Uses

  • Commercial resale or redistribution of puzzles
  • Automated scraping, crawling, or data mining
  • Reverse engineering our puzzle generation algorithms
  • Introducing viruses, malware, or malicious code
  • Attempting to gain unauthorized access
  • Harassment, abuse, or harmful conduct toward others

⚠️ Violation Consequences: We reserve the right to suspend or terminate accounts that violate these terms. Serious violations may be reported to appropriate authorities.

3. Intellectual Property Rights

The Service and its original content, features, functionality, design, and algorithms are owned by Sudoku Evil and are protected by international copyright, trademark, patent, trade secret, and other intellectual property laws.

What We Own

  • Puzzle Generation Algorithms: Our proprietary difficulty balancing and puzzle creation systems
  • Original Content: Educational articles, strategy guides, tutorials, and blog posts
  • Design & Branding: Logos, color schemes, UI designs, and visual identity
  • Software Code: Frontend and backend code, APIs, and technical infrastructure
  • Database & Datasets: Curated puzzle collections and user analytics (anonymized)

Your License to Use

We grant you a limited, non-exclusive, non-transferable, revocable license to:

  • Access and use the Service for personal, non-commercial purposes
  • Print puzzles for personal or classroom educational use (not for resale)
  • Share links to puzzles via our share functionality
  • Embed our widgets on educational or non-commercial websites (if we provide such features)

What You CANNOT Do

  • Copy, modify, or create derivative works from our content or code
  • Sell, rent, lease, or sublicense access to our puzzles or Service
  • Remove copyright notices, trademarks, or proprietary markings
  • Republish our puzzles in books, apps, or other platforms without written permission

Educational & Fair Use: We support educational use. Teachers and schools may use our puzzles in classrooms at no cost. For commercial licensing or bulk redistribution, please contact us.

4. User Content and Conduct

If we offer features like comments, forums, or user-generated content (e.g., custom puzzles), you retain ownership of your content but grant us a license to use it.

Content You Submit

By posting, uploading, or sharing content on our Service, you grant us a worldwide, non-exclusive, royalty-free license to use, display, reproduce, and distribute your content for the purpose of operating and promoting the Service.

You promise that: Your content does not violate any laws, infringe on others' rights, contain malware, or include offensive material.

Community Standards

  • Be respectful and courteous to other users
  • Do not post spam, advertisements, or promotional content
  • Do not share personal information of others without consent
  • Do not impersonate others or misrepresent your identity
  • Report violations to us via our contact page

5. Service Availability and Modifications

We strive to provide a reliable, high-quality Service, but we cannot guarantee uninterrupted or error-free operation.

Service Availability

  • The Service is provided "as is" and "as available"
  • We may perform scheduled maintenance with advance notice
  • Emergency maintenance may occur without notice
  • We aim for 99.5% uptime but do not guarantee it

Service Modifications

  • We may add, remove, or modify features at any time
  • Significant changes will be announced via the Site
  • We reserve the right to discontinue the Service with 30 days' notice
  • Your data export will be available before discontinuation

Free Service: Our core Sudoku puzzle service is and will remain free. If we introduce premium features, existing free features will not be removed.

6. Disclaimer of Warranties

IMPORTANT LEGAL NOTICE: The Service is provided "AS IS" and "AS AVAILABLE" without warranties of any kind, either express or implied.

To the fullest extent permitted by law, we disclaim all warranties, including but not limited to:

  • Merchantability: The Service is suitable for general use
  • Fitness for a Particular Purpose: The Service meets your specific needs
  • Non-Infringement: The Service does not violate third-party rights
  • Accuracy: Puzzle solutions, scores, or statistics are always correct
  • Availability: The Service will be available at all times
  • Security: The Service is completely secure from cyber threats

Medical Disclaimer: While Sudoku may have cognitive benefits, our Service is not medical advice and should not replace professional healthcare. Consult a doctor for medical concerns.

Educational Disclaimer: Our tips and strategies are for general guidance. Educational outcomes depend on many factors beyond our control.

7. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW: Sudoku Evil, its directors, employees, partners, agents, suppliers, and affiliates shall NOT be liable for:

  • Indirect, Incidental, or Consequential Damages: Loss of profits, data, use, goodwill, or other intangible losses resulting from your use or inability to use the Service
  • Service Interruptions: Temporary unavailability, errors, bugs, or technical issues
  • Third-Party Actions: Unauthorized access to your account, data breaches by hackers, or malicious third-party activities
  • User Content: Content posted by other users, including offensive or illegal material
  • External Links: Content on third-party websites linked from our Service

Maximum Liability Cap

In jurisdictions where liability cannot be excluded, our total liability to you for any claims arising from these Terms or your use of the Service shall not exceed the greater of:

  • The amount you paid us in the 12 months before the claim (if any), OR
  • $100 USD

Exceptions: Some jurisdictions do not allow exclusion of certain warranties or limitation of liability for incidental or consequential damages. In such cases, the above limitations may not apply to you.

8. Indemnification

You agree to defend, indemnify, and hold harmless Sudoku Evil and its affiliates, directors, employees, and agents from any claims, damages, losses, liabilities, and expenses (including legal fees) arising from:

  • Your Use of the Service: Any way you access or use our Service
  • Terms Violations: Your breach of these Terms or any applicable law
  • Your Content: Content you post that infringes on others' rights or violates laws
  • Third-Party Rights: Violation of any third-party intellectual property or privacy rights
  • Harmful Conduct: Actions that harm other users or third parties

Simple Translation: If your actions cause legal trouble for us, you're responsible for the costs and consequences.

9. Termination

You Can Leave Anytime

  • Stop using the Service at any time
  • Delete your account via account settings
  • Download your data before deletion
  • No penalties or fees for cancellation

We May Terminate or Suspend

  • Immediately for Terms violations
  • For abusive or harmful behavior
  • For suspected fraud or illegal activity
  • With notice if discontinuing the Service

What Happens to Your Data

Upon account deletion or termination:

  • You have 30 days to download your puzzle progress and statistics
  • Personal data will be deleted according to our Privacy Policy
  • Anonymized analytics data may be retained for research purposes
  • Public content (e.g., forum posts) may remain but will be anonymized

Survival: Sections that should reasonably survive termination (like intellectual property, disclaimers, and liability limitations) will remain in effect.

10. Dispute Resolution and Governing Law

Governing Law

These Terms are governed by and construed in accordance with the laws of [Your Jurisdiction], without regard to its conflict of law provisions.

Informal Resolution First

Before filing a claim, please contact us at our contact page to try to resolve the dispute informally. Most issues can be solved through friendly communication.

We'll respond within 7 business days and work in good faith to resolve the issue within 30 days.

Arbitration (If Required)

If informal resolution fails, disputes will be resolved through binding arbitration rather than in court, except where prohibited by law.

  • Arbitration will be conducted by a neutral arbitrator
  • Each party pays their own arbitration costs
  • You retain the right to pursue claims in small claims court if eligible
  • Class action lawsuits are waived (individual claims only)

EU/Consumer Rights: If you're in the EU or a jurisdiction with consumer protection laws, you may have additional rights that cannot be waived by this agreement.

11. Changes to These Terms

We reserve the right to modify these Terms at any time. When we make changes, we will:

How We Notify You

  • Minor Changes: Update the "Last Updated" date at the top of this page and post a notice on the Site for 7 days
  • Material Changes: Email registered users at least 30 days before changes take effect (if you've provided an email)
  • Significant Changes: Display a prominent banner on the Site requiring acknowledgment before continued use

Your Options

If you disagree with modified Terms:

  • Stop using the Service before the changes take effect
  • Delete your account and download your data
  • Contact us with feedback (we do listen!)

Continued use of the Service after changes take effect constitutes acceptance of the new Terms.

We believe in transparency. Check this page periodically to stay informed about our Terms.

12. Miscellaneous Provisions

Entire Agreement

These Terms, along with our Privacy Policy, constitute the entire agreement between you and Sudoku Evil.

Severability

If any provision is found invalid or unenforceable, the remaining provisions continue in full force.

Waiver

Our failure to enforce any right or provision does not constitute a waiver of that right or provision.

Assignment

You may not assign or transfer these Terms. We may assign our rights and obligations to any successor or affiliate.

Force Majeure

We're not liable for delays or failures caused by events beyond our control (natural disasters, wars, pandemics, etc.).

No Agency

Nothing in these Terms creates an employment, partnership, agency, or joint venture relationship.

Questions About These Terms?

We're here to help. If anything in these Terms is unclear or you have specific questions about what's allowed, just reach out.

Contact UsRead Privacy Policy

Remember: We're Here to Help

These Terms are designed to protect both you and us while keeping Sudoku Evil free, fun, and accessible. We've tried to write them in plain English and be as fair as possible.

  • Use the Service respectfully and legally
  • Don't abuse or exploit our systems
  • Respect others' intellectual property and privacy
  • Contact us if you have questions or concerns

Thank you for being part of the Sudoku Evil community!