Terms of Service

1. Acceptance of Terms

By accessing or using Locus, you agree to be bound by these Terms of Service and our Privacy Policy. If you do not agree to these terms, please do not use our service.

These terms constitute a legally binding agreement between you and Stel Studio Inc, the company that operates Locus. By creating an account or using the platform, you acknowledge that you have read, understood, and agree to be bound by these terms.

2. Description of Service

Locus is a competitive mathematics learning platform that provides:

• Interactive mathematics problems across various topics
• ELO-based rating system for competitive learning
• Leaderboards and progress tracking
• Personalized problem recommendations
• User accounts and profile management

We reserve the right to modify, suspend, or discontinue any aspect of the service at any time without prior notice.

3. User Accounts

3.1 Eligibility

You must be at least 13 years old to use Locus. By creating an account, you represent that you meet this age requirement and that all information you provide is accurate and complete. This applies to an account you create for yourself on locusmath.org. Student accounts created by a school are covered by section 3.5 instead.

3.2 Account Registration

To use certain features, you must create an account. You agree to:

• Provide accurate and current information
• Maintain the security of your password
• Accept responsibility for all activities under your account
• Notify us immediately of any unauthorized access

3.3 Account Security

You are responsible for maintaining the confidentiality of your account credentials. Do not share your password with others or allow others to access your account. You agree to notify us immediately of any security breach.

3.4 Account Termination

We reserve the right to suspend or terminate your account at any time for violations of these terms, including but not limited to:

• Cheating or unfair play
• Creating multiple accounts
• Harassment or abusive behavior
• Violation of applicable laws

3.5 Schools and Student Accounts

Locus for schools runs on class.locusmath.org. A school or district that wants student accounts signs a data privacy agreement with us first. That agreement governs student data and takes precedence over these terms wherever the two differ; the school authorizes the accounts of its own students, of any age, for educational use.

Students sign in only through their school's Google or Clever account and hold student accounts, which have no password, cannot buy anything, and never appear on public leaderboards or profiles. Teachers use ordinary accounts, and these terms apply to them in full. To request the agreement, or for a privacy review, write to privacy@locusmath.org.

4. User Conduct

You agree to use Locus in a fair and respectful manner. Prohibited activities include:

4.1 Cheating and Unfair Practices

• Using automated tools or bots to solve problems
• Sharing or receiving answers to problems
• Creating multiple accounts to manipulate ratings
• Exploiting bugs or vulnerabilities for unfair advantage
• Coordinating with others to artificially inflate ratings

4.2 Prohibited Behavior

• Harassment, bullying, or threatening other users
• Posting offensive, inappropriate, or illegal content
• Attempting to gain unauthorized access to the platform
• Reverse engineering or decompiling platform code
• Interfering with the proper functioning of the service
• Impersonating other users or Locus staff

5. Intellectual Property

5.1 Platform Ownership

The Locus platform, API, software, design, text, graphics, and logos are the proprietary property of Locus and are protected by copyright and intellectual property laws.

5.2 Problem Content

The mathematical problems and the scripts used to generate them are licensed under the MIT License. This means you are free to use, copy, modify, and distribute the problems and generation scripts, subject to the terms of the MIT License.

5.3 User Content

You retain ownership of your account data and problem-solving history. By using Locus, you grant us a limited license to use this data to provide and improve our service, including displaying your progress and rankings on leaderboards.

5.4 Usage Restrictions

You may not:

• Copy, modify, or reverse engineer the platform or API code
• Use the platform infrastructure for commercial purposes without authorization
• Remove copyright notices or proprietary markings from the platform

6. ELO System and Rankings

6.1 How Ratings Work

Locus uses an ELO-based rating system to track your skill level. Your rating changes based on:

• Successfully solving problems (rating increases)
• Failing to solve problems (rating may decrease)
• The difficulty of problems attempted

6.2 Fair Play Expectations

The integrity of the rating system depends on fair play. We expect all users to:

• Solve problems independently without external assistance
• Not manipulate the system through multiple accounts
• Report bugs or rating issues promptly

6.3 Rating Adjustments

We reserve the right to:

• Recalculate ratings if errors or cheating are detected
• Reset ratings in cases of system changes or updates
• Remove users from leaderboards for violations

7. Paid Subscriptions

Locus offers optional paid subscriptions: Locus Insider (billed yearly) and developer plans for the Locus Problems API (billed monthly). Payments are processed by Stripe; we never see or store your card details. Subscriptions renew automatically until canceled, and you can cancel at any time from Settings (or, for API plans, the API dashboard); cancellation stops the next renewal and keeps your access until the end of the paid period.

• Full refund within 7 days of any payment, no questions asked, from Settings or by contacting us. A refund ends your subscription immediately.
• Prices may change; renewals are charged at the price shown in Settings before renewal.
• Subscriptions are not available on student accounts.
• If we discontinue a paid feature, we will refund the unused portion of your subscription.
• API plans are volume quotas with hard caps: at the cap, further requests are refused until the quota window resets, and there is no overage billing. Upgrading replaces the lower plan; the superseded plan's most recent payment is refunded.
• API keys are credentials for your account. Keep them secret: anything done with your key counts against your quotas and is treated as your use. Keys are shown once at creation and stored by us only as a cryptographic hash; we cannot recover a lost key, but you can revoke it and create another at any time.
• A paid subscription does not change the "as is" basis of the service (Section 8). We target 99.5% monthly uptime but do not guarantee availability, and no service credits are offered; your remedies for downtime are the refund and cancellation rights in this section.

8. Disclaimers and Limitation of Liability

7.1 Service Provided "As Is"

Locus is provided on an "as is" and "as available" basis. We make no warranties, express or implied, regarding:

• Accuracy or completeness of content
• Uninterrupted or error-free service
• Fitness for a particular purpose
• Security of data transmission

7.2 Limitation of Liability

To the maximum extent permitted by law, Locus shall not be liable for:

• Any indirect, incidental, or consequential damages
• Loss of data, profits, or opportunity
• Service interruptions or technical failures
• Actions of other users on the platform

7.3 Educational Use

Locus is an educational tool designed to supplement your mathematics learning. We do not guarantee specific educational outcomes, test scores, or academic success. Your progress depends on your effort and dedication.

9. Indemnification

You agree to indemnify and hold harmless Locus, its affiliates, and personnel from any claims, damages, or expenses arising from:

• Your use of the service
• Your violation of these terms
• Your violation of any rights of another party
• Your violation of applicable laws

10. Changes to Terms

We may modify these Terms of Service at any time. When we make significant changes, we will:

• Update the effective date at the top of this page
• Notify you via email or platform notification
• Provide a reasonable notice period before changes take effect

Your continued use of Locus after changes take effect constitutes acceptance of the modified terms. If you do not agree with the changes, you should discontinue use of the service.

11. Governing Law and Dispute Resolution

These terms are governed by and construed in accordance with applicable laws. Any disputes arising from these terms or your use of Locus shall be resolved through:

• Good faith negotiations between the parties
• Mediation or arbitration if negotiations fail

12. Contact Information

If you have questions about these Terms of Service, please contact us at:

Email: support@locusmath.org

13. Severability

If any provision of these terms is found to be unenforceable or invalid, that provision shall be limited or eliminated to the minimum extent necessary, and the remaining provisions shall remain in full force and effect.

14. Entire Agreement

These Terms of Service, together with our Privacy Policy, constitute the entire agreement between you and Stel Studio Inc regarding your use of the service and supersede any prior agreements.