Developer tooling · 2026 · Solo — research, product design, build, verification
Cache Window
An interactive HTTP cache-policy inspector for seeing exactly when a response is fresh, stale, or origin-bound.
The problem
HTTP caching encodes freshness, validation, shared-cache overrides, and stale allowances in a terse response header. MDN and the HTTP caching standards document those rules separately; Cache Window makes a deliberately supported subset inspectable without claiming to emulate every browser or CDN.
Architecture
Key decisions
Explain a bounded standards subset
The MVP names the directives it evaluates and labels unknown input instead of pretending to be a complete cache implementation. Validators, Vary, request directives, clock skew, and vendor behavior remain explicit exclusions.
Make time the primary interaction
A response-age scrubber moves a signal cursor through fresh, background-revalidation, error-fallback, and expired regions, turning delta-seconds into one inspectable spatial model.
Command / Inspect, not dashboard
The composition pairs one editable header with one dominant state readout and ruled timeline—no marketing hero, fake chart, decorative metric grid, or invented product usage.
Ship behind local and production gates
Ten core tests, lint, typecheck, build, the Foundry harness, invalid-input probes, responsive checks, and HTTPS golden paths all passed before portfolio integration.