Create a custom offline page and configure a service worker, a browser background script, to cache it in advance. Show it when page navigation fails, and review resource dependencies and fallback conditions.
Use when adding PWA capabilities, implementing a service worker, or improving the experience for users on unreliable network connections.
This skill helps you create a custom information page for times when a lost connection prevents a page from opening. It prepares an /offline page that works without external network requests. A service worker, which handles network requests in the browser, caches this page during installation. When a page navigation request fails, it returns the saved information page.
Use it when preparing a site for use as a PWA or helping users understand what is happening on an unreliable connection. Instead of the browser's standard error screen, you can show guidance about what to do while offline. It also helps you review the behavior of an existing service worker.
/offline page and cache it in advance with the service worker.”The implementation requires a service worker. The information page must work without external resources and be cached during installation. Confirm that the fallback applies only to page navigation requests, and is not returned for individual resources such as images.
This overview was written by AI (OpenAI Codex) from the public SKILL.md. Check the original below for the exact behavior.
AI rated this skill on four points using only the contents of its SKILL.md. Stars and popularity are not taken into account.
The total counts each point as A = 25, B = 15, C = 5. Rated by AI (OpenAI Codex) as of Oct 23, 2026. Treat it as a guide and read the original before installing.
Review the instructions the agent will receive before you install.
The browser's default offline error screen ("No internet connection") is confusing and completely outside your brand. A custom offline page maintains the user experience, reinforces trust, and can surface cached content or useful actions — such as enabling users to continue reading a cached article or queuing a form submission for later.
Check whether the site shows a custom offline fallback page when the network is disconnected and a navigation request cannot be fulfilled.
Create a self-contained /offline page and configure the service worker to pre-cache it and serve it for failed navigation requests.
Explain how a service worker can intercept failed network requests and return a cached offline fallback page to the user.
Review the service worker fetch handler and the offline page markup. Verify the offline page is pre-cached at install time, that it does not depend on external resources, and that the fallback is only served for navigation requests (not sub-resources).
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/performance/offline-fallback
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