Differential is designed to work without asking for your FPL password or account login.
If you choose My Team, the FPL manager ID you enter is remembered in a first-party cookie on your device so the site can reopen your public FPL squad. You can remove it at any time using “Not you?” on My Team.
Differential also records privacy-light product events such as page views and labelled feature interactions so we can understand which parts of the product are useful. These events intentionally exclude your FPL manager ID, search text, passwords and form contents.
Public football and FPL data shown on the site comes from the official FPL API and other identified data sources used by the product. Differential does not ask for or store your Fantasy Premier League password.