Privacy

Privacy, in plain words

Kids use Slices, so we collect as little as we can. You can use every lesson without telling us anything about yourself.

Without an account

Your progress (which questions were answered, and when) is saved in your browser’s local storage, on your device. It isn’t sent to us.
There are no ads, no advertising trackers, no analytics cookies and no social media widgets.
Fonts and images come from Slices itself, so your browser doesn’t contact other companies while you learn.
You can download or clear your progress at any time from My progress.

With a free account

Accounts are for grown-ups (parents, caregivers and teachers) and teenagers 13 and older. Before you make one, we ask for a month and year of birth. If someone younger tries, we explain that a grown-up can set one up instead. We don’t keep the birth date.

What we store: your email address (or your Google account’s email, if you sign in with Google) and your learning progress. Nothing else.
Where: with Google Firebase Authentication and Cloud Firestore. Security rules let only you read or change your progress.
Why: to keep your progress safe and in sync across devices, and to open the account extras. We never sell or share it, and we never use it for advertising.
Your choices: sign out at any time (and clear progress from a shared device if you like), and delete your account from the account page, which also deletes the progress saved in it.

Donations

If you donate, you pay on our payment provider’s page, not on Slices. Your card details go to them, never to us.

Children

Children don’t need an account and are never asked for personal information. There is no chat, no messaging and no public profile of any kind, and learning histories are never shared. If you believe a child under 13 has made an account without a grown-up, a parent or guardian can delete it from the account page while signed in.

Changes

If this notice changes, we’ll post the new version here with a new date.

Last updated: October 2026.