Cookie Policy

1. What cookies and browser storage are

Cookies are small text records the browser stores for a website; localStorage and sessionStorage are similar browser stores that never leave your device by themselves. YoluBand uses all three. Azerbaijani data-protection law applies to any of them that contain personal data, and this policy plus our Privacy Policy describe exactly that.

2. Strictly necessary cookies

These are required for the service to work; they cannot be switched off from within the app:

• Sign-in session (Clerk): several cookies set by our authentication provider keep you signed in securely and expire with your session.
• NEXT_LOCALE: remembers your interface language (Azerbaijani, Russian, English).
• yb.theme, yb.skin, yb.frame: remember your light/dark theme and cosmetic choices so the page renders correctly before it loads.

3. Functional cookies

These make features work but the app survives without them:

• Placement cookies (yb_placement, yb_placement_sid): carry the result of a pre-signup placement test to your new account, then are cleared.
• Referral cookie (yolband_ref): remembers for 30 days that you arrived via a friend's invite link so both of you can receive the referral reward.
• Teacher-link cookie (yolband_teacher): remembers a pending teacher connection or that you declined one.
• Preference and dismissal cookies (yb_tool_uses, yb_streak_repair_dismissed, yb_vocab_suggest_dismissed, yb_find_level_dismissed): remember a free-tool usage counter or that you closed a banner so we do not show it again.

4. Analytics (optional; you can decline)

We use PostHog, hosted in the European Union, for first-party product analytics: which screens are used, where learners get stuck, whether new features help. PostHog sets cookies (names starting with ph_) that keep a stable identifier so we can see, for example, whether learners return a week later.

• Analytics events carry your user ID and event names, never the text of your essays, your audio, your tutor chats, or your email address.
• The first-visit notice lets you decline analytics with one click; declining stops analytics capture in your browser.
• Our product analytics honours your browser's Do Not Track setting.
• Separately, our hosting provider measures traffic and page performance for us (Vercel Web Analytics and Speed Insights); this measurement sets no cookies and stores no cross-site identifier.
• Your consent choice itself is stored in localStorage (yolband:consent_v1).

5. Local and session storage we use

Kept on your device to make the app feel instant; none of it is advertising-related:

• yolband:consent_v1: your analytics-consent choice.
• yb.theme: theme fallback used before the page finishes loading.
• yb.voiceConsent: a local flag that you have given voice-recording consent, so this device does not ask again (the authoritative consent record is stored with your account).
• Campaign snapshot (yb.utm_first): if you arrived from a link with campaign tags (UTM), a first-touch snapshot so we know which channel brought you.
• Sound and input preferences (yb_input_hard_mode and the sound-effects switch): typing-mode and sound choices.
• Game and streak helpers (yb_daily_word, yb_league_result_seen, and per-game bests): local bests for mini-games, daily-streak helpers, and flags that mark a celebration you have already seen.
• Lesson-variant memory (yb.variantSeen.v1): which wording variant of an exercise you saw last, so repeats feel fresh.
• Feedback-prompt counters (yolband:nps_v1, yolband:lesson_count): local counters that decide when to show the occasional feedback prompt.
• Writing-draft autosave: mock-test essay drafts saved locally so a crash or refresh does not lose your writing.
• Offline queue: lesson answers saved while you are offline (in the yolband-pwa browser database), synced when you reconnect.
• Offline app cache: copies of app files and authored lesson audio (CacheStorage) so pages load fast and work offline.
• Install-prompt flags (yb.pwa.installDismissedAt, yb.pwa.lessonCompletions): remember that you dismissed the install-app prompt and how ready this device is for it.
• Session-only flags: one-shot helpers (for example, scrolling to your placed unit once) that disappear when the tab closes.
• QA marker (yb_qa): set by hand only on our own test devices so our team's usage is excluded from analytics; it is never set for real users.

6. How to control cookies, changes, and contact

You can decline analytics from the first-visit notice; if you cleared your browser storage, the notice appears again on your next visit. You can also delete or block cookies entirely in your browser settings; the app will still work, though you will be signed out and your preferences reset. Material changes to this policy are announced through an in-app notice; the date at the top is the effective date. The Azerbaijani-language version of this policy is the governing version. Questions: privacy@yoluband.az.