Privacy

No account, no email

Using Lemma does not need your name, email address, or a password. When you start, it mints a random learner id and stores it in a signed cookie on your device. That id is the only thing that ties your study record to you. If you want the same record on another device, Account gives you a link that carries the id for 30 days; treat it like a key.

What is stored

• Your study record — the problems you have worked, each step you entered, which skills you have shown independently, your spaced-review schedule, your notes and scratch ink, and your tutor conversations. This is the whole of what the app needs to pick up where you left off.
• Study events — a timestamped log of attempts, hints, diagnoses, and outcomes. They are what the progress views are built from. When you start, the log also notes which website sent you (the site name only), which Lemma page you started on, and whether you were on a phone, tablet or computer, so we can tell which pages help people get going. Milestones such as “first answer box opened” are logged once, with no step text.
• Daily tutor usage — how many tutor asks (10/day), voice sessions (3/day), and handwriting reads (40/day) you have used today, so the free allowance can be enforced. Counts reset every day (UTC).

Everything is kept in one database on Cloudflare. Step checking is done by Lemma's own symbolic verifier on the server; nothing about a step leaves Lemma unless you ask the tutor.

The optional waitlist

The landing page has one optional form: leave an email address to be told when full access opens. Nothing in the app needs it. If you use it, Lemma stores the address, the page it came from, and when it was added, and uses it only for that message. A notification with a masked form of the address (for example ra***@gmail.com) may be posted to a private channel the maintainer reads, so a new signup is noticed. To count repeated attempts from one network, the form keeps a one-way hash of your IP address for the current hour only. To be removed from the list, email randy@roviqai.xyz.

Lemma in ChatGPT

If you use the Lemma plugin in ChatGPT, ChatGPT sends Lemma the math problem and the steps you asked it to check (and, for a study plan, your test date and hours per week). Lemma checks them with its own symbolic verifier while the request is open and does not store them: they are not written to a database, a file or a log, and Lemma never sees your name, email, ChatGPT account or conversation. What Lemma keeps from this is anonymous counts only: how often each tool was used, whether a check could be completed, how many steps there were, which kind of line could not be read, and which practice topic was shown. They contain no problem text, no steps, no identifier and no network address, and Cloudflare deletes them on its own schedule, at most seven days after the call. To keep one busy user from slowing the service for everyone, Lemma uses the anonymous user id that ChatGPT attaches to each call (or, when there is none, the network address) as a counter key for under a minute; it is not written down or kept. The only recipients are ChatGPT (OpenAI), which sent the request and receives the result, and Cloudflare, which hosts the service and processes network addresses transiently to deliver and protect it. If you open a practice link from ChatGPT, the link carries a source tag (utm_source=chatgpt) and the topic, which Lemma records once as the source of a new study record. Practice links open lemmamath.app, where the rest of this policy applies, including the Google Analytics described below. Lemma in ChatGPT is for adult learners and is not directed to children under 13.

What goes to an AI provider

When you ask the tutor a question, start a voice session, or have handwriting read, Lemma sends the AI provider your typed (or spoken) question, the current problem, your verified work on it so far, and — for handwriting — an image of the line you wrote. It does not send your name (it does not have one), your learner id, or your history beyond that problem. Lemma's default tutor, voice and handwriting models are Google's Gemini (with other providers such as Fireworks or Microsoft Azure used as fallbacks or for a few older accounts). Providers process this to answer and may hold it briefly under their own terms; Lemma does not use it to train anything.

Google Analytics

Lemma uses Google Analytics to count visits and see which pages and buttons are used. It records page views and events such as starting practice or answering a question, with your approximate location and device type, using Google's cookies. It does not receive your typed steps, your learner id or any email address. You can block it with a browser extension or your browser's tracking settings, and Lemma works the same without it.

What is not done

• No ads, and no advertising trackers.
• No selling or sharing of your record with anyone.
• No cookies other than the session cookie that keeps you signed in and the cookies Google Analytics sets (see below).

Deleting your data

You can delete your data at any time from Account ("Delete my data"), or by sending POST /api/account/delete while signed in. This removes your study record, your event log, your topic history, and your usage counts for earlier days in one step and clears the cookie. Today's usage count is kept until the day ends, because it is the day's spend against a paid provider and not part of your study record; it is then removed automatically, within about a day. There is no recovery afterwards, so export what you want first.

Children

Lemma is not for children under 13. If you are under 13, please do not use it.

Contact

Questions about any of this: randy@roviqai.xyz.