Cookie Policy
Last updated: 26 October 2026
What are cookies?
Cookies are small text files stored on your device when you visit a website. They help the site function correctly and remember your session.
Cookies we use
Maths Monster uses strictly essential cookies only. These are required for the website to function and cannot be switched off. We do not use any analytics, advertising or third-party tracking cookies. We count visits to our public pages with Umami, which runs on our own server, sets no cookies and stores nothing on your device.
| Cookie | Purpose | Duration |
|---|---|---|
__Secure-better-auth.session_token | Keeps you logged in | Session / 30 days |
__Secure-better-auth.session_data | A short-lived copy of your login, so pages load faster | 5 minutes, or until you close your browser if you chose not to stay logged in |
__Secure-better-auth.dont_remember | Remembers that you chose not to stay logged in | Until you close your browser |
mm_child_token | Keeps your child logged in on their own device | 90 days |
mm_active_child | Remembers which child's profile is open on your device | 30 days |
cf_clearance | Bot check on login and sign-up (Cloudflare Turnstile) | 30 minutes |
mm_referral_code | Records which referral link you arrived through | 30 days |
mm_last_checkout | Stops you being charged twice for one subscription. It gives no access to your account. | 180 days |
mm_checkout_browser (local storage, not a cookie) | Same purpose as mm_last_checkout. It holds a random tag only. | Until you clear your browser's site data |
Service worker sw.js (browser storage, not a cookie) | A small script your browser installs on your first visit, so it can show practice reminders if you later allow them. It stores no personal data. | Until you clear your browser's site data |
| Notification subscription (browser storage, not a cookie) | Created only if you allow notifications. It is a device address that we link to your account, so reminders reach the right device. | Until you turn notifications off or clear your browser's site data |
mm_teacher_grid_v1 (local storage, not a cookie) | Teachers only: remembers the sort order, filters and layout of the progress grid. | Until you clear your browser's site data |
Third-party cookies
We do not set any third-party cookies ourselves. Two things on the site can load a third party's own cookies: the payment processor (Stripe) on the Stripe checkout page, governed by Stripe's privacy policy; and, on lesson pages that include curated YouTube videos, Google — which connects as the page loads, and whose embedded player may set further cookies once you or your child presses play (see our Privacy Policy, section 7).
Cookie consent
Because we only use strictly essential cookies, a cookie consent banner is not legally required under UK GDPR / PECR. Essential cookies are exempt from the consent requirement as the Service cannot function without them.
The mm_referral_code cookie is a first-party cookie used only to remember which
referral or affiliate link a visitor arrived through, so that a referral can be credited correctly
if the visitor later subscribes. It is not used for cross-site tracking, advertising, or building a
profile of your browsing activity, and no data from it is shared with third parties. That said, it
is arguably not "strictly necessary" to deliver the specific service a visitor has requested in the
way that the session cookie is — it exists to support our referral programme rather than to make
the site work — so its classification under PECR regulation 6 is not clear-cut. We are treating it
as essential for now on that narrow attribution purpose, but if that position turns out not to be
defensible we will introduce a consent mechanism for it.
Managing cookies
You can delete cookies at any time through your browser settings. Note that deleting the session cookie will log you out.
Contact
Questions about our cookie use? Email privacy@maths.monster.