Legal
Cookie Policy
Last updated 2 October 2026.
1. What we use
phdflow uses a single strictly-necessary cookie, plus browser local storage for your preferences. If you accept it in the cookie notice, we also load OpenAI's ad measurement pixel, which sets one advertising cookie; without your consent it is never loaded. We do not use analytics cookies. We do count page visits, but we do it on our own servers without setting anything on your device; see section 3a of the Privacy Policy for how that works.
| Name | Type | Purpose |
|---|---|---|
| phdflow_session | Essential (cookie) | Keeps you signed in (a signed session identifier). Required for the app to work. |
| phdflow-theme | Preference (local storage) | Remembers your chosen color theme. |
| phdflow-consent | Preference (local storage) | Remembers your answer to the cookie notice. |
| __oppref | Advertising (cookie, OpenAI), only with consent | Holds the reference of the ChatGPT ad you clicked, so OpenAI can tell us whether that click led to a purchase. Set by OpenAI's measurement pixel, which loads only after "Accept all". |
2. Consent
The session cookie is strictly necessary, so it does not require consent. The ad measurement pixel needs it: the cookie notice asks first, and "Essential only" keeps it switched off. You can change your answer at any time with the button below.
3. Controlling cookies
You can clear or block cookies in your browser settings. Blocking the session cookie will prevent you from staying signed in.
See also our Terms of Service and Privacy Policy.