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LV2 · Toolooo Standard
Explore → See → Understand → ActUnderstand it. Feature Level describes the depth of the tool experience.

HTTP Cache Lab

Configure Cache-Control, ETag, and Last-Modified headers and simulate how browsers and CDNs actually cache the response.

EngineeringBackendNetworkingAPI
5m
Response headers
Cache-Control: public, max-age=300
ETag: "a1b2c3-etag"

Live: what happens right now

3m
max-age (5m)FRESHSTALE — REVALIDATEFETCH (t=0)HIT · 3m0s10m
What happened
At 3m since the first fetch, a request for this resource is a HIT.
Why
Still fresh — served straight from cache with no network request at all.
Try
Drag past max-age (5m) to see it flip from HIT to REVALIDATE, or toggle ETag/Last-Modified to see which validator saves a full re-fetch.

Quick reference — three fixed points in time

✓
Immediately after (1s): HIT
Still fresh — served straight from cache with no network request at all.
✓
Halfway through max-age (3m): HIT
Still fresh — served straight from cache with no network request at all.
ℹ
After max-age expires (8m): REVALIDATE
Stale by the clock, but the ETag allows a cheap conditional check (If-None-Match → maybe 304).

Understand HTTP Cache Lab

What this tool helps you understand

Set response caching headers on a mock request and step through what a browser and a CDN would actually do with them — serve from cache, revalidate, or fetch fresh — so HTTP caching semantics stop being guesswork.

When to use it

Use HTTP Cache Lab when engineering, backend, and networking work raises questions about http caching, cache-control header, and etag and you need a concrete view before making the next move.

How to read the result

Compare the shape and direction of different scenarios. The useful signal is how the result changes when an input changes, rather than one isolated number.

Assumptions and limits

This is a simplified explanatory model, not a load test or production forecast. Real systems can include dependencies, distributions, failures, and feedback loops outside the selected inputs.

Toolooo is part of Khizooology, created byKhizar Imtiaz (khizooo).