ABOUT
A small tool with a narrow job.
Cache rules fail quietly. A TTL that outlives a purge, a cache key that splits on tracking parameters, an open CORS header on a response that should never have had one — none of it throws an error, it just behaves wrong for weeks.
The idea
Write the rule as a form, and have something read it back to you before it reaches production. Most of these mistakes are visible in the values alone; you do not need a live edge to notice that a browser TTL of a day sits behind an edge TTL of an hour.
Why it runs locally
Configuration says where your origin lives and how your sessions are recognized. There is no reason for that to leave the browser, so it does not. The page makes no network requests after it loads — no analytics, no fonts from a third party, no validation call.
What it refuses to do
It will not claim a hostname resolves, a certificate is valid, an origin answers or a cache is warm. It cannot check any of that without contacting them, and it does not contact them. Where a figure would have to be invented, the page says so instead of showing a number.
Scope
Two output formats and a JSON dump, one route per rule, one saved list per browser. There is no team workspace, no sharing link and no account, and none of those are planned — the moment this tool stores your configuration somewhere other than your own browser, the reason to trust it goes away.