COOP COEP CORP generator

This page assembles header values; it does not know your server's routes or your CDN's behavior, so preflight headers like Access-Control-Allow-Methods stay yours to write. The credentialed CORS block exists because one static Access-Control-Allow-Origin value cannot serve an allowlist: your server has to read the request's Origin and reflect it only when it matches. After deploying an isolation bundle, document.crossOriginIsolated in the console is the real verdict.