Daily Math Friends is a personal app that gives adults one math puzzle a day, tracks how long it took to solve, and lets you compare with friends you've explicitly added. This page explains, in plain language, what data the app handles and why.
What we collect
The only data Daily Math Friends collects is what you give it directly:
- Account identifiers. When you sign in we store an email address and a Supabase-issued user ID. If you sign in with Apple or Google, we receive whatever identifier and email those providers return — Apple may relay an anonymized email if you choose Hide My Email.
- Profile. The display name you set on first launch, an auto-generated username, and an 8-character invite code that lets friends add you.
- Daily puzzle attempts. For each day you play, we record the puzzle date, your submitted answer, whether it was correct, and the time it took (in milliseconds). This is what makes the leaderboard and streak features work.
- Friend graph. The list of users you have added as friends, and any pending invite-code requests you have sent or received.
We do not collect device identifiers for advertising, location data, contacts, photos, microphone audio, browsing history, or any data you have not entered into the app.
How we use it
Your data is used solely to provide the app's features: signing you in, serving you the day's puzzle, recording your time, and showing you side-by-side with the friends you have explicitly added. It is not used for advertising, analytics, profiling, or sale to third parties. Friend rankings are visible only to people in your direct friend circle — not to other users of the app.
Where it is stored
All Daily Math Friends data lives in a Supabase
Postgres database operated as the app's backend, in a dedicated math
schema. Every table is protected by Postgres row-level-security policies so that you
can only read and write data tied to your own account or your direct friends.
Authentication tokens are stored on your device in the iOS Keychain (via
expo-secure-store) and never written to disk in plain text.
The same Supabase project also hosts the data for TripSharing, our other app, so a single account works in both. The two apps' data live in separate Postgres schemas and never read each other's tables.
Notifications
If you enable the daily reminder in Settings, the app schedules a single repeating local notification on your device at a fixed time. This is handled entirely by iOS or Android — no notification token is sent to our servers, and we do not run a push infrastructure. You can revoke notification permission at any time from your device's system settings, or toggle the reminder off inside the app.
Third parties
- Apple and Google are used for native sign-in. They authenticate you and return an identity token; they do not see your puzzle data.
- Supabase hosts the database, authentication service, and stored files on the app's behalf. They are a data processor, not a recipient of your data for their own use.
What we don't do
- No analytics SDKs, no third-party tracking, no advertising.
- No selling or sharing of your data with anyone for any purpose.
- No access to your phone's contacts, location, photos, or other system data.
- No server-side push notifications. The daily reminder is scheduled and fired entirely by your device.
Your rights
You can, at any time:
- Edit your display name from the app's Settings screen.
- Remove a friend by deleting the friendship row through the in-app friends list (or ask us to do it for you).
- Toggle the daily reminder off from Settings, which cancels the scheduled local notification.
- Request deletion of your account and all associated puzzle attempts, friendships, and profile data by emailing matthewzhenghi@gmail.com. We will confirm and remove your data within 30 days.
Children
Daily Math Friends is aimed at adults — particularly parents who want a daily mental workout — and is not directed to children under 13. We do not knowingly collect data from anyone under 13. If you believe a child has created an account, contact us and we will remove it.
Changes to this policy
If we materially change how data is handled, we will update this page and bump the effective date at the top. For substantive changes, the next app release will surface a notice the first time you open it.
Contact
Questions, deletion requests, or anything else: matthewzhenghi@gmail.com.