What is Service Worker? — UK Software Development Guide

Service Workers have specific UK GDPR implications. Service Workers can cache personal data in the browser — this data must be treated as personal data under UK GDPR: it must be cleared on logout, right to erasure requests must clear the Service Worker cache, and the Privacy Notice must disclose that data is stored locally in the browser. For NHS and FCA regulated applications: Service Workers caching clinical or financial data offline must be carefully controlled — a shared device (clinical workstation, library computer) where another user accesses Service Worker cached personal data from a previous session is a personal data breach. ClickMasters implements Service Worker scope restrictions and cache clearing on session end for regulated sector applications.