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# Service worker checker

Fetch a page URL and its service worker script through the capped proxy, locate the page's service-worker register call, and statically report on HTTPS scheme, MIME type, install, activate, fetch, and message handlers, and Cache API use without executing anything.

Static inspection, never execution
This tool reads a page's markup and its worker script as text. The worker never runs here, and no registration is created in your browser.

A static read has honest blind spots. A registration added by a separate bundle, an argument built at runtime instead of a quoted string, or listeners attached through a helper instead of a literal addEventListener call will not show up here, and this tool does not claim a site's offline mode works or that it would pass a Lighthouse audit. It reports what the text contains.
OptionsCheck service worker

## More web & auth tools

- [HTTP header parser](/web/headers)
- [CSP evaluator & builder](/web/csp)
[All web & auth tools](/web)

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Canonical HTML: https://nutter.tools/web/service-worker-checker
Markdown version: https://nutter.tools/web/service-worker-checker.md
Plain-text version: https://nutter.tools/web/service-worker-checker.txt
Agent index: https://nutter.tools/llms.txt