Privacy Policy

1. Introduction

undefined.fun is an anonymous, instruction-less, browser-based puzzle experience. This policy describes how we collect, use, and protect information when you use our site. We aim to be transparent and respectful of your privacy.

2. Information we collect

Anonymous use

You can play puzzles without creating an account. In that case we do not collect personally identifiable information. Session cookies may be used to remember your progress through the puzzle sequence within a single browser session.

Registered accounts

If you register, we collect and store: your email address, a securely hashed password, and a public display name (handle). We use your email to verify your account and to let you log in. Your handle is shown on the leaderboard when you complete puzzles.

Game progress

For registered users, we store which puzzles you have completed, your solve times, and attempt counts. This data powers your profile and the leaderboard. Anonymous users do not have persistent progress stored on our servers.

Donations and payments

If you donate, payment processing is handled by Stripe and related payment method providers. We store donation metadata such as payment intent identifiers, amount, status, and receipt references for accounting, fraud prevention, and support. We do not store full payment card numbers on our servers.

3. Cookies and sessions

We use session cookies for authentication. When you log in, we store an encrypted session token in a cookie so you can stay signed in. The session lasts up to 30 days. You can log out at any time to clear your session.

4. How we use your information

• To provide and improve the puzzle experience
• To maintain your account and game progress
• To display leaderboard rankings (handle and solve times only)
• To communicate with you about your account (e.g. email verification) if applicable
• To enforce our Terms of Service and protect the site

5. Security and activity logs

For abuse prevention, account security, and admin moderation, we may store account activity events such as sign-ins, password changes, and puzzle progression milestones. These records can include masked IP data, user-agent information, and event metadata needed to investigate suspicious or harmful behavior.

6. Third-party links

We may show referral links or banner ads (e.g. to partner services) after completing puzzles or on the coming-soon page. Clicking these links takes you to external sites. We do not control those sites or their privacy practices. We encourage you to read their privacy policies.

7. Analytics, advertising, and diagnostics

We may use analytics, tag-management, and advertising tools to understand usage, improve performance, and support operations. These services may use cookies or similar technologies subject to their own policies. We may also process operational diagnostics (for example, server logs and health telemetry) to detect abuse, monitor reliability, and troubleshoot incidents.

8. Data retention and deletion

We retain your account data and progress for as long as your account exists. If you wish to delete your account and associated data, contact us and we will process your request within a reasonable time.

9. Security

We store passwords using industry-standard hashing (bcrypt). We do not store plaintext passwords. We use HTTPS for all traffic. While we take reasonable steps to protect your data, no system is completely secure; use the site at your own risk.

10. Installed app behavior

On supported devices and browsers, you may be offered install prompts or home-screen guidance. If you install the app-like experience, some preferences (such as dismissing install prompts) may be stored locally on your device.

11. Children

undefined.fun is intended for general audiences. We do not knowingly collect personal information from children under 13. If you believe we have done so, please contact us so we can remove the information.

12. Changes

We may update this policy from time to time. The “Last updated” date at the top will change when we do. Continued use of the site after changes constitutes acceptance of the updated policy.