Privacy Policy

Numi is a math practice app for children, set up and managed by a parent or guardian. This policy explains what we collect, why, and what control you have. We do not sell personal information, and we do not use it for advertising.

Who the account belongs to

Numi accounts are created by an adult. Children do not create accounts, do not log in separately, and are never asked for personal details. A child profile is simply a name (or nickname) and a grade level that the parent enters.

What we collect

• Parent account: your email address, and a password (stored only as a salted hash — we never see it). If you sign in with Google or Apple we receive your email address and name from them. You may optionally add a display name.
• Child profiles: the name or nickname you enter, the grade level, and practice preferences. Use a first name or nickname — nothing more is needed.
• Practice activity: the problems generated, your child's answers, whether they were correct, time spent, and the handwritten scratch work drawn on the practice pad (saved as an image so you can review it later).
• Technical basics: ordinary server logs needed to operate and secure the service.

We do not collect location, contacts, photos, microphone, or camera data. Numi contains no advertising and no third-party analytics or tracking software.

How we use it

To create and secure your account; to generate practice problems at the right level; to grade answers and give feedback; to show you your child's history and highlight the topics they find hardest; and to process payment if you upgrade.

Service providers we use

Running Numi means using a small number of outside services, and some of them necessarily handle your information to do their job. They act only on our instructions and only for the purposes above: none of them may use your information for their own purposes, and we do not hand anything to anyone else. What each one handles:

• DeepSeek and OpenAI — generate practice problems, grade answers, and write the step-by-step explanations. Either may handle a given request: Numi uses one by default and automatically switches to the other if it is unavailable, so both should be treated as receiving this data. What they receive is the problem text, your child's typed answers, and the grade level. Handwritten drawings are never sent. Child names are not sent.
• Railway — hosts the app and the database, so your account details and everything saved to it (child profiles, practice history, and the handwritten scratch work) are stored on their infrastructure.
• Resend — delivers account emails (verification and password reset), so it handles your email address and the contents of those messages. It is not used for marketing.
• Stripe (web) and Apple / RevenueCat (iOS app) — process payments, which means your email address and payment details. Card details go directly to them; we never see or store them.
• Google and Apple — only if you choose to sign in with them, and only to confirm your identity. Signing in shares your name and email address with us; we share nothing back.

We do not sell or rent personal information, and we do not share it for advertising. We may disclose information if required by law.

How long we keep it

Practice history is kept so you can review your child's progress, until you delete it or delete your account. You can clear a child's history, or remove a child profile, at any time in the app.

Deleting your account

You can permanently delete your account from Account → Delete account inside the app. Deleting removes your account, every child profile, all practice history, and all saved scratch work from our database. This cannot be undone. If you would rather we do it, email us at hello@nexusaistudio.studio from your account address.

Children's privacy

Numi is designed for children to use under the supervision of a parent or guardian, who creates the account and controls it. We do not knowingly collect personal information directly from children, and nothing in the app asks a child for personal details. Parents can review or delete their child's information at any time using the controls described above. If you believe a child has provided us information directly, contact us and we will remove it.

Security

Traffic is encrypted in transit (HTTPS). Passwords are stored only as salted hashes. Access to the production database is restricted. No system is perfectly secure, but we take reasonable measures to protect your information.

Changes

If this policy changes materially we will update the date above and, where appropriate, notify you by email.

Contact

Questions about this policy or your data: hello@nexusaistudio.studio