Privacy Policy
Trident Calculator · Last updated: October 2026 (draft)
Trident is a calculator for students and teachers. We built it to collect as little as possible. This page explains what that means in plain language.
The short version
- No ads. Trident shows no advertising, ever.
- No tracking. No analytics or tracking SDKs, no advertising identifiers, no cross-app or cross-site tracking, no fingerprinting.
- No account needed. Every calculator works without signing in. Your work stays on your device.
- We never sell or share your data with advertisers or data brokers.
What stays on your device
Trident saves each calculator's state (memory, history, lists, graphs, programs and modes) and your settings (skin, appearance, language, display options) in your device's or browser's local storage, so the app picks up where you left off. This never leaves your device unless you turn on sync. Deleting the app, or clearing your browser's site data, removes it.
Optional sync
If you choose Sign in to sync, you sign in with Apple or Google. We then store, in Google Firebase (Cloud Firestore), linked to your sign-in account:
- your sign-in account's ID and the display name or email your provider gives us (with Sign in with Apple you can hide your email);
- each calculator's saved state and your app settings, with the time each was last changed.
This is used only to keep your calculators the same on your devices. Only you can read or change it. If you sign out, your data stays on your devices. To delete your synced data and account, contact us (below) and we will delete it. Sync is not available to people under 13 (see Children).
Purchases
- In the iPhone and iPad app, Trident Pro is bought through Apple's App Store. Apple handles payment; we never see your card or Apple ID details. The app checks your purchase with Apple on your device.
- On the web, Trident Pro may be bought through our payment provider Polar (polar.sh), which handles payment and emails you a license key. Polar's own privacy policy covers the details you give it at checkout. To check that a key or pass is valid, the website sends the key and a random browser label (like
web-a1b2c3d4) to Polar or to our pass service. - "Use Pro on the web": if you ask the iPhone app for a web pass code, it sends Apple's signed proof of your purchase to our pass service, which checks it with Apple and returns a code. We store the code, a transaction number from Apple and the browser labels where the code is active. No name or email is involved.
Children
Trident is used by students, including children under 13. Without sync, Trident collects no personal information from anyone. Before sign-in, Trident asks whether you are 13 or older; if you answer no, sync is not offered and no account is created. We do not knowingly collect personal information from children under 13. If you believe a child under 13 has signed in, contact us and we will delete the account and its data. Parents and schools can use every calculator without any account.
Service providers
- Netlify: hosts the website. Like any web host it processes basic request data (such as IP address) to deliver pages.
- Google Firebase: sign-in and storage, only if you turn on sync.
- Apple: App Store purchases and Sign in with Apple. Polar: web purchases.
Changes
If this policy changes, we will update the date above, and for significant changes we will say so in the app.
Contact
Questions or deletion requests: [CONTACT - owner to add a support email or form].