Cassie: Privacy Policy

Last updated: 20 October 2026

Cassie is a free study helper. She works as a web app, a phone app and a Chrome extension. This page tells you, in plain words, what Cassie keeps, what she sends to other companies, and how to delete your things.

The short version

Cassie uses AI. To answer you, she sends your question to an AI service run by another company. They are all named below.
Your files, photos and voice are not kept. Cassie uses them to answer you, then lets them go. Our server does not save them and does not write them in any log.
Most of your things stay on your device. Your chats, flashcards and settings live in your own browser.
We never sell your data. There are no ads and no trackers.

What stays on your device

These are saved in your own browser or phone. They do not go to us.

Your chats with Cassie. If you attached a file, the chat keeps its name and the first part of its words, so you can ask more about it later. Photos are not kept in your chats.
Your profile: your name or nickname, your age and your school level. Cassie uses it to explain things at the right level.
Your flashcards, your quiz mistakes, what Cassie remembers about you, and your settings.
Your own AI keys, if you add them. They are only sent to the company the key belongs to.
In the Chrome extension: your last 60 questions and answers, small pictures of your last 10 snips, your keys, and your last 20 lessons (the page title, what Cassie said in each step, and a small picture of the page with her drawings). Lessons stay on this device until you delete them in the Cassie side panel.

What Cassie sends to other companies

When you ask something, Cassie sends what you asked (your words, and any photo, file text or voice) to one of these services so it can make an answer. If you have not added your own key, it goes through Cassie's server first, and our server passes it on. Each company follows its own privacy rules.

Groq: writes most of Cassie's answers, reads photos, and turns your voice into words.
Anthropic (Claude): writes answers for people on the Plus and Pro plans.
Google Gemini: writes answers when Groq is busy, reads photos and files, makes pictures, and looks things up on the web with Google Search when you ask for a web answer. If you add your own Gemini key, a PDF you attach is sent to Google whole.
Cloudflare: runs Cassie's website and server. Its Workers AI is our backup. It can write answers, read photos, turn voice into words and make pictures.
ElevenLabs: reads Cassie's answers out loud in her studio voice. It only gets Cassie's answer, never your files. The sound file is kept in Cloudflare's cache for up to 30 days, so the same sentence is not made twice.
Pollinations: makes pictures from a short written description. It never gets your photos.
OpenAlex: finds real research papers for the topic you give when you use Research.
Wikipedia and the World Bank: give facts about the country or place you look up in the World atlas.
Google and Apple: if you sign in with them, they tell Cassie your email and first name. Also, when you talk to Cassie, your browser may turn your voice into words by itself. In Chrome that is done by Google, and in Safari by Apple.

Your files, photos and voice

PDFs, Word files and PowerPoints are read on your own device. Only their words (or pictures of the pages, for scanned files) are sent, to one of the services above, to answer you. Photos, voice recordings and pictures of your board are sent the same way. Cassie's server passes them on and then drops them. It keeps no copy, and it never writes them, or their names, in any log or table. We test this every time Cassie changes.

What Cassie's server keeps

Counts for fair limits. How many questions, pictures and minutes of voice were used today, so everyone gets a fair share. These counts use your internet address (IP address) or a random number made by your device. They are deleted when the day ends. Weekly and monthly picture and voice allowances are kept until the week or month ends.
Anonymous usage counts, if you leave them on: a random number made by your device, when Cassie opened, which feature you used, and broad groups only (student or working, school level, age range, phone or computer, language). If you are 18 or older and leave "topic words" on, up to five single words from a typed question (like "photosynthesis") are counted. Never your messages, files, photos or name. Nothing at all is counted for children under 13. You can turn these off in Settings, You.
A count when Cassie answers with care. If you tell Cassie you want to hurt or kill yourself, she answers with care and shows a free crisis hotline. We count that it happened, with nothing else: not your words, not your name, not any number for your device.
Problem reports. If you use Report a problem, we keep what you type, the feature, and the broad groups above. Please do not type personal details. When something breaks and usage counts are on, the app also sends which error message it showed (like "network"), never the words of your question or file.
Your account, if you make one: your email, a scrambled copy of your password (never the password itself), your first name, your profile and settings, your quiz mistakes and up to 500 flashcards, so they follow you to other devices. If you sign in with Google or Apple, we keep which one and its number for you. Your chats, files, photos and keys are never saved to your account.
Study rooms. What you share in a room so the others can see it: your first name, your drawings, notes, flashcards, chat messages, quiz answers and where your pointer is. Anyone with the room code can join. Rooms and everything in them are deleted after one day.
Daily puzzles. Your first name and your time, for the score board. Kept for 14 days.

How to delete your things

Your account: Settings, You, Delete account. This removes your account, your plan and your sign ins from our server right away.
One chat: open the menu and delete it there. What Cassie remembers: open Memory and tap Clear all memory.
Everything on this device: clear this site's data in your browser settings, or remove the app or the extension.
Usage counts and problem reports: turn usage counts off in Settings, You. The counts are not linked to your name, so we cannot find yours. To delete a problem report, email us when you sent it and what it said.

Children

Cassie is for learners of every age. Children should use Cassie, and make an account, with help from a parent, guardian or teacher. For children under 13, Cassie sends no usage counts and no error reports.

What Cassie does not do

No selling or sharing of your data for ads. No ads and no trackers.
The extension only reads a page when you highlight text, snip, tap Teach me or Ask Cassie, or click Cassie's button. What Teach me and Ask Cassie read is sent to the AI for that answer only and is never kept. The lesson Cassie teaches you stays on this device until you delete it. It does not collect your browsing history or what you type.

Changes

If this page changes, the date at the top changes too.

Contact

Questions, or want something deleted? Email [email protected].