Cached Middleware Fetch Demo

Cache Status

MISS

cachedFetch() Duration

1369.89ms

API Response Timestamp

2026-03-03T21:09:59.122Z

Random Value (to verify cache)

0.403881

Cache Age

0 seconds

Current Time

2026-03-03T21:09:59.156Z

How it works:

The proxy fetches from an API endpoint that has a 1000ms delay
Uses SWR (Stale-While-Revalidate) caching strategy with separate revalidate and expiry times
Cache HIT: Fresh cached data served instantly (~0-5ms)
Cache STALE: Cached data served instantly, background refresh triggered via waitUntil() (~0-5ms)
Cache MISS: No cached data available, full API delay incurred (~1000ms)
Data is fresh for 5 seconds (revalidate time)
After 5 seconds, data becomes stale but is served instantly while refreshing in background
After 30 seconds, cache expires completely and requires a fresh fetch
The random value helps verify when the cache is actually being used
Cache status provided via response headers: X-Cache-Status, X-Cache-Age, X-Cache-Expires-In