Cookie policy
Last updated: September 26, 2026
Also: TermsPrivacyCookiesUsage policy
1. What are cookies
Cookies are small text files stored on your device when you visit a website. They help the site remember your session and preferences.
2. Cookies we use
We store cookies and read them in line with article 399 of the Polish Electronic Communications Law (Prawo komunikacji elektronicznej) and the GDPR. Essential and preference cookies are necessary to provide the Service, so they do not require prior consent. Analytics cookies are set only after you agree in the cookie banner.
- Essential cookies: Required for authentication and security (Supabase session).
- Preference cookies: Remember display settings such as view mode and language preferences stored locally or in your account.
- Analytics cookies: If enabled, help us understand how the Service is used (for example PostHog). These are not required to use BrainAIstorm.
Show the cookies we use
| Cookie | Purpose | Lifetime |
|---|---|---|
| sb-...-auth-token (Supabase, may be split into numbered parts) | Keeps you signed in | While you stay signed in; refreshed automatically, removed when you sign out |
| bas_locale | Remembers your language choice | 12 months |
| bas-analytics-consent | Records your analytics choice from the cookie banner so our servers can honor it | 180 days, refreshed on later visits |
| bns_device_fp_... (sessionStorage, not a cookie) | Set after you sign in to remember that this browser has already registered its device signature for abuse prevention | Until you close the tab |
| Device signature (computed in your browser, not stored) | A hash of your browser and system information (user agent), screen size, timezone and language, sent to us after you sign in for abuse prevention; nothing is written to your browser | Not stored in your browser |
| bas-cache:... (localStorage, not a cookie) | Keeps the last screen you saw (counts, the titles of your decisions, your name, your plan, your thinking style label, display preferences) so the app opens without waiting. Never the text of a decision, its analysis or your assessment answers. | 2 days; removed when you sign out or when your session ends |
| ph_..._posthog (PostHog) | Product analytics, set only after you accept analytics | Up to 12 months |
Your consent choice is also stored in your browser's localStorage, and PostHog uses localStorage alongside its cookie. The last-known screen entry above is also localStorage; it is there so the app opens without a blank moment and holds no decision text. If you accept analytics, Sentry session replay also uses your browser's sessionStorage while it records.
3. Managing cookies
You can control cookies through your browser settings. Disabling essential cookies may prevent you from logging in or using core features.
You can change your analytics choice at any time using the cookie settings link in the footer.
4. More information
For how we handle personal data, see our Privacy policy.