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Service workers, fetch(), and CORS: interception limits you should know
Workers can intercept navigations and same-origin fetches, but cross-origin requests still follow browser CORS rules.
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service-workerpwacors
Scope and same-origin
Service workers run in a separate context with their own lifecycle; they cannot override CORS decisions made by the browser for opaque responses.
Caching strategies should store responses you are legally allowed to persist—respect Vary: Origin when applicable.
Offline PWAs
Pre-cache static assets on your origin; for APIs, prefer explicit same-origin wrappers or documented proxies.
Test update flows so a bad worker version does not strand users without CORS-aware fallbacks.