Privacy Policy

1. About this policy

This policy covers the Sumzo website and the Sumzo apps for iPhone and Android (together, the “Service”). “Sumzo”, “we” and “us” mean the team that runs the Service.

If you have a question about your information, please contact us.

2. What we collect

• Your account: your email address and your password. We never store your password itself — only a secure, one-way scrambled version (a hash) that can check it but not reveal it.
• Your learning profile (optional): your learning stage, goals, how confident you feel, your preferred explanation level and your unit system (metric or US). Every question is optional.
• What you solve: the problems you type and the photos, screenshots or PDFs you attach, and the answers Sumzo gives. When you are signed in with history saving on, these are saved to your account so you can find them again. You can switch history saving off at any time.
• Practice and calculators: when you are signed in, your practice answers (whether each was right) and the calculations you choose to save.
• Messages to us: if you use the contact form or report a wrong answer, we keep what you send (for a report: the problem, the answer and your note) so we can reply and fix mistakes.
• Sign-in and security: the devices you are signed in on (shown to you as, for example, “Chrome on Windows” or “Sumzo app”), the last time each was used, and short-lived records that limit repeated attempts (for example too many wrong passwords). These records use scrambled keys, not your raw email or IP address.
• Counts without personal information: how many questions were solved and how (maths engine or Sumzo AI), how many AI requests were made and how large they were, and technical errors on our servers (the page and the error, never what you typed). None of these include who you are.

We do not collect your name (unless you put it in a message), your date of birth, your location, your contacts or advertising identifiers.

3. Cookies and storage on your device

We only use what is needed for the Service to work. There are no advertising or tracking cookies and no third-party analytics.

• sumzo_session keeps you signed in on the website.
• sumzo_signed_in tells the page you are signed in so it can show the right menu (it holds no information about you).
• sumzo_device remembers a device you trusted, so you are not asked for an emailed code for 30 days.
• sumzo_login and sumzo_restore hold a sign-in or account-restore step for a few minutes.
• sumzo_guest is a random code that lets us apply the fair-use limits on Sumzo AI to visitors who are not signed in. It expires after 7 days without use.
• Your browser also remembers a few choices, such as your explanation level and unit system, on your own device.
• In the app, your sign-in is kept in your phone’s secure storage (Keychain on iPhone, Keystore on Android).

4. How we use your information

• To provide the Service: solve your problems, explain the steps, and keep your history, practice and calculations for you.
• To keep accounts safe: sign-in codes, device management, and limits on repeated attempts.
• To keep Sumzo AI fair and affordable for everyone: daily and per-minute limits.
• To reply to your messages and fix wrong answers you report.
• To understand, in total numbers only, how the Service is used and where it breaks, so we can improve it.
• To send emails you need: sign-in codes, email confirmation, password resets, security notices and replies to your messages. We do not send marketing emails.

5. Sumzo AI and the companies that help us

Problems that Sumzo’s own maths engine cannot solve are answered by Sumzo AI, which uses Anthropic’s Claude models. To answer, we send Anthropic the problem, any photos or PDFs you attached and, for follow-up questions, the solution you are asking about. We do not send your name or email address.

Anthropic processes this content to produce the answer, under its commercial terms and privacy policy. Please don’t include personal details in your problems or photos.

We also use a hosting provider to run our servers and store data, and an email provider to send emails. They may only use your information to provide those services to us.

6. When information is shared

We never sell your information or share it for advertising.

• When you create a share link for a solution, anyone with the link can see that solution (not your account or other history) until the link expires or you turn it off.
• With the service providers described above, only to run the Service.
• If the law requires it, or to protect people’s safety or the Service from abuse.

7. How long we keep it

• Saved solutions, photos, practice answers and calculations: until you delete them or your account.
• Your account: until you delete it. After you ask, it is kept for 7 days in case you change your mind (log in during that time to restore it), then permanently deleted with everything in it.
• Data downloads you request: available for 24 hours.
• Share links: until they expire (1, 7 or 30 days, as you choose) or you turn them off.
• Messages and wrong-answer reports: one year after the last activity.
• Sign-in codes: 10 minutes. Fair-use counters: 24 hours.
• Server error records: 30 days. Total-only counts: about 13 months.
• Copies in backups disappear as old backups are replaced.

8. Your choices and rights

• Switch history saving off, or delete single solutions, at any time in Privacy & data or in the app.
• Change your learning profile in your account (on the website or in the app).
• Download a copy of your data from Privacy & data.
• Delete your account from Privacy & data on the website, or from Account in the app.
• See and sign out the devices you are signed in on in Sign-in & security.

Depending on where you live, you may also have the right to ask what information we hold about you, to have it corrected or deleted, to object to how we use it, and to complain to your data-protection authority. Contact us and we will help.

9. Children

Sumzo is for learners aged 13 and over. Children under 13 may use it only with the permission and supervision of a parent, guardian or teacher, as our Terms of Use explain.

We collect only what the Service needs and nothing that identifies a child beyond an email address for an account. If you are a parent or guardian and want a child’s information deleted, contact us.

10. Keeping your information safe

Information travels over encrypted connections (HTTPS). Passwords are stored only as secure hashes, sign-ins need an emailed code on new devices, and repeated attempts are limited. Only the people who run Sumzo can reach the stored data.

No system is perfectly secure. If something goes wrong that affects your information, we will tell you and the authorities where the law requires it.

11. Changes to this policy

If we change this policy, we will update the date at the top. If a change is significant, we will tell signed-in users by email or on the site before it takes effect.

12. Contact

Questions or requests about your information? Contact us.