Stale-while-revalidate

Best of both worlds

Stale-while-revalidate serves cached content immediately for speed, then updates the cache in the background. Users get instant feedback while fresh data is fetched asynchronously.

Stale-while-revalidate implementation

Serve from cache immediately, fetch fresh data in background, update cache.

self.addEventListener('fetch', event => {
  event.respondWith(
    caches.open('v1').then(cache => 
      cache.match(event.request).then(response => {
        const fetchPromise = fetch(event.request).then(networkResponse => {
          cache.put(event.request, networkResponse.clone());
          return networkResponse;
        });
        return response || fetchPromise;
      })
    )
  );
});

Output:

Cached content served instantly; fresh version fetched and cached in background.

Quick check

Quick check: What is the main benefit of stale-while-revalidate?

• Instant response to users while fresh data updates in background
• Always serving the newest content
• Reducing server load completely