Privacy
What we collect — and what we don't.
Mercurius AI teaches AI literacy. Hiding how the app itself handles your data would make a poor lesson. So here is the full picture, in plain language, for students and for parents.
Effective: September 27, 2026 · We update this page whenever the facts change.
Who Mercurius is for
Mercurius AI is built for teens aged 13 to 18. If you are under 13, you may not use it.
Starting with app version 2.3, the app asks how old you are the first time you open it. The age picker starts on "Select your age", and you have to choose an age before you can continue. If you pick an age under 13, the app shows a screen saying Mercurius is for ages 13 and up instead of the tutor. There is no button on that screen to go back and pick again.
This device then remembers that stop for 7 days, even if you close and reopen the app. All it keeps is when the stop happened, never your age. Your age is only checked on your device, and it is never sent to us or saved.
There are no accounts. You never give us a name, an email address, or a password.
What we collect
A random session ID. When you open the app for the first time, Mercurius generates a 32-character random identifier and stores it in the iOS Keychain on your device. The server sees this ID on every request so it can recognize you across sessions for features like streaks, quizzes and your lesson checklist. It is not tied to your name, email, phone number, or any external identity. If you use Mercurius in a web browser, the ID is kept in that browser's storage instead, and your messages, photos and lesson checklist are handled the same way as below.
Your messages. Every chat message you send, and every lesson transcript, goes to our server and is forwarded to Anthropic's Claude API to generate the reply. Messages are stored on our server under your session ID for 90 days so features like the quiz and the report card can look back at your recent turns. The conversation you see in the app lives on your phone.
Photos you attach. If you attach a photo to a message (a worksheet, a screenshot), it takes the same path as a message: to our server, then to Anthropic to generate the reply. Photos are deleted from our server after 24 hours.
Content you report. If you report a reply as wrong or harmful, that reply and the message you sent just before it are saved as a report on our server for the developer to review. A notice about the report — never the text — goes to a private Discord channel that only the developer reads.
Your lesson checklist. Which lessons you finished and which units you passed are saved on our server under your session ID, whichever app version or browser you use. From app 2.3, that lets your path come back if you reinstall the app. A lesson you have only started stays on your device.
Usage rows. For each request we record which feature was used, how many tokens it took, and what it cost. The rows are filed under your session ID so we can apply daily limits. They contain no message content.
Lesson events. Rows that record when a lesson was started, each answered turn, and when it was finished, filed under your session ID, so we can see whether the lessons work. They contain no message content.
A scrambled network address. Your phone's IP address is scrambled with a secret key before anything is written down. We store at most the scrambled version, never the raw address, and we use it only to protect the service from abuse. The server holds the raw address in memory just long enough to count each network's usage for the day.
What we don't collect
- No accounts, names, or emails. Mercurius doesn't ask for an account and doesn't have one. No name, email, phone number, or password.
- No contacts, no location. The app never reads your contacts and never asks for your location.
- No advertising identifiers. We don't read the device advertising ID, and there are no ads.
- No third-party analytics SDKs. No Google Analytics, no Facebook Pixel, no tracking libraries. None.
- Nothing is sold. Your messages are not sold, shared for advertising, or used to target you with anything.
- No device fingerprinting. The session ID is randomly generated, not derived from your device.
- No push notifications from us. Reminders are off until you turn them on in the app, and your phone schedules them itself. We never receive a push token or your reminder times.
What "not linked to you" means in practice
On our server, your conversations sit under a random string of letters and numbers. There is no name, email, or phone number next to it. If someone looked at the database, they would see what was said, but not who said it.
The exception is you. If you type your full name, your school, or your address into a chat, that text is stored with the rest of the message. The tutor doesn't need those details, so please leave them out.
We never store the real network address, and we never try to work it back out from the scrambled one.
Who sees what
Three outside services touch your data. Two of them see message content. The third gets short notices that never contain anything you typed.
- Anthropic — Claude. Runs the language model that writes the replies. Every message and photo is sent to Anthropic's API to generate a response. Their terms are at anthropic.com/legal. Anthropic does not train future models on API requests by default.
- Railway — hosting. Hosts our server and database in the United States. Standard hosting provider; it holds the encrypted traffic and the database that stores conversations.
- Discord — notices for the developer. When you report a reply, a notice goes to a private Discord channel that only the developer reads. It has the report's number, the reason, which part of the app and which mode it came from, the lesson (if there was one), the app version, how long the reported reply and your message before it were (a character count, not what they said), and the first eight characters of your session ID. The reported text itself stays on our server. The same channel gets the server's own alerts: a daily summary of totals (active students, lessons, cost), server status, spending and error warnings, and the scrambled address of any network that reaches its daily limit. None of these notices contain message text, and they stay in the channel after the data they describe is deleted.
Anthropic and Railway are the only companies that process message content. We do not share, sell, or transfer your messages to anyone else.
How long we keep it
Deletion is automatic. You don't have to ask for any of these.
| What | Kept for |
|---|---|
| Chat and lesson messages | 90 days |
| Photos you attach | 24 hours |
| Content reports | 180 days, whether or not we have reviewed them. |
| Usage rows | 400 days |
| Lesson events | 400 days |
| Your lesson checklist | Until you delete your data, or the whole session is erased |
| The whole session | Erased entirely, with everything above, after 365 days with no activity |
Your controls
- Delete everything from inside the app. Open Settings and tap "Delete my data & start over." This erases everything on our server tied to your session ID — messages, photos, reports, usage rows, lesson events and your lesson checklist — and gives you a brand-new ID. From the server's point of view you have never been here before. Available in app version 2.3 and later; on an older version, update the app or use the email option below.
- Withdraw consent. Settings → Privacy choices → Withdraw consent erases the same data and shows the first-launch agreement again before you can chat.
- Or email us. Write to privacy@trymercurius.com and paste your session ID, which is shown in Settings. We delete the data within 7 days.
- Deleting the app is not enough. Removing Mercurius from your phone does not delete what is on the server. Use one of the options above, or wait for the automatic limits in the table.
For parents and schools
There is no account to review and no name on file, so we cannot look up a student by name. What we can tell you: the app is for ages 13 and up, it asks for an age at first launch and shows anyone who picks one under 13 a stop screen instead of the tutor for 7 days (the check takes the student's word for it, and the device keeps only when the stop happened, never the age), it collects no contacts or location, it shows no ads, and everything it stores is deleted on the schedule above or on request.
If you want a student's data deleted, ask them to use the button in Settings, or email us their session ID. Questions from a parent or school go to privacy@trymercurius.com and we answer them ourselves.
Contact
Privacy questions and deletion requests: privacy@trymercurius.com
Everything else, including bugs and feature questions: support@trymercurius.com or the Support page.