Cookie Policy
Last updated: 19 October 2026
> Courtesy translation. Only the French version is legally binding: Politique cookies. In the event of any discrepancy, the French text prevails.
1. What is a cookie?
A cookie is a small text file placed on your device (computer, smartphone, tablet) when you visit a website. The local storage (localStorage and sessionStorage) of your browser or of the app plays a comparable role. The regulations apply to both in the same way: they are referred to as “trackers”.
This policy applies to the derja.fr website and to the Derja mobile apps (iOS and Android).
Our domain places no cookies. Everything Derja stores on your device is kept in local storage, and is described below.
2. Trackers needed for the service
They serve only to make the service you request work. The law does not require your consent for these trackers.
| Tracker | Content | Purpose | Duration |
|---|---|---|---|
sb-[reference]-auth-token (local storage) | Session token (JWT) | Staying signed in between visits | Until you sign out |
| Settings (local storage) | Language, sounds, automatic voice playback, exercise audio, microphone refusal | Keeping your preferences | Until cleared |
| Profile copy and offline progress (local storage) | Latest copy of your profile, save and stars waiting to be sent | Carrying on playing without a connection, without losing anything | Until synchronised; the profile copy, until you sign out |
| Interface state (local storage) | Messages, banners and guided tour already seen, step of the discovery path, dates of review requests | Not showing you the same thing twice | Until cleared |
| Website files (browser cache) | Derja's pages, images and sounds | Opening the website faster, and offline | Until replaced or cleared |
| In-app purchases (mobile app) | User identifier and status of your purchases, kept by the RevenueCat module | Knowing which subscription is active | Until the app is uninstalled |
The session token is created by the Supabase library when you sign in. Without it, signing in to the service is impossible.
3. Audience measurement trackers
Derja's audience measurement, carried out with PostHog (hosted in the European Union), produces anonymous statistics, compiled from a random identifier specific to the device, never linked to your account. It uses no data taken from your account and serves only to measure how Derja is used and to detect technical errors in it. It thus meets the conditions set by the CNIL for audience measurement trackers exempt from consent (deliberation no. 2020-091 of 17 September 2020, article 5). The details of the data sent are in the privacy policy, section 2.4.
| Tracker | Content | Purpose | Duration |
|---|---|---|---|
ph_[key]_posthog (local storage) | Random device identifier, session identifier, origin of the first visit, PostHog settings kept in cache | Audience measurement | 13 months at most from the first measurement, never extended; then erased and replaced |
derja_mesure_debut (local storage) | Date | Enforcing the 13-month limit | Same duration as the identifier |
ph_[key]_… (session storage) | Technical data for the current session | Audience measurement | As long as the tab is open |
derja_mesure_refus and __ph_opt_in_out_[key] (local storage) | Your refusal of measurement | Remembering your choice | Until cleared |
Objecting to this measurement, at any time: use the “Anonymous audience measurement” switch, in My account (“Data & legal” section) or at the bottom of the home page, available without signing in. Your browser's Do Not Track or Global Privacy Control setting has the same effect. PostHog is then no longer loaded and the random identifier is erased from your device; only your choice remains. Data already sent is linked only to the random identifier, never to an account.
Events sent from the website before 14 October 2026, and those sent by versions of the mobile app released before the October 2026 update, were still linked to your account identifier, using a cookie. They remain with PostHog until they expire, 12 months at most. For this data, you can write to us at contact@derja.fr: we delete in PostHog the data linked to your account. On the device, that cookie and the old identifier are erased the first time the updated version is launched.
4. Partner code
If you arrive at Derja through the link of a partner content creator (an address ending in ?p= followed by their code), that code is saved in your device's local storage.
| Tracker | Content | Purpose | Duration |
|---|---|---|---|
derja_affilie (local storage) | Code of the link and date of arrival | If you create an account, attributing it to the partner who introduced you to Derja | 30 days at most; erased as soon as it is recorded on your new account |
The code is read only when an account is created: it is then recorded once only on your profile, to pay the partner, and erased from the device. It is not used for any advertising, and the partner receives only totals, never any data about you. It is also attached, as the origin of the visit, to the audience measurement. You can erase it at any time by clearing the website's data (see section 7).
5. What Derja does not use
Derja does not use:
- advertising or targeting cookies;
- social network cookies (Facebook pixel, TikTok, X, LinkedIn, etc.);
- tracking from one site or app to another;
- fingerprinting (identifying a device by its technical characteristics);
- fonts or scripts loaded from third-party servers: fonts are hosted on our own servers.
6. Third-party services
Some services used by Derja have their own pages, which place their own cookies on their own domain, under their own rules:
- Stripe: when you pay on the website, you are taken to Stripe's payment page, which may place its own cookies, necessary for payment security. See: https://stripe.com/fr/privacy
- Google and Apple: if you sign in with one of these accounts, its sign-in page may place its own cookies. See: https://policies.google.com/privacy and https://www.apple.com/legal/privacy/
7. Clearing cookies and local storage
On the website, you can clear the local storage of derja.fr at any time from your browser settings:
- Chrome: Settings > Privacy and security > Cookies and other site data > See all site data and permissions
- Firefox: Settings > Privacy & Security > Cookies and Site Data > Manage Data
- Safari: Settings > Privacy > Manage Website Data
In the mobile app, uninstalling the app erases all this data.
Note: clearing this data signs you out of the service and erases your settings, including any refusal of audience measurement. Your progress, however, remains saved in your account.
8. Contact
For any question about this policy:
Email: contact@derja.fr
Mail: Ismael Dubuc, 30 Allée Sidney Bechet, 93430 Villetaneuse, France