demo · v146
Preflight inspector
Pick an initiator (public site, private site, local file) and a target (public, private LAN, loopback). The inspector replays the full Local Network Access decision: address-space classification, preflight scheduling, the Access-Control-Request-Private-Network headers, the response check, and the final allow / prompt / block verdict.
This is the kind of tool you reach for when a fetch suddenly fails in production. Run it against your site shape, get a step-by-step rationale, and copy the headers your endpoint needs to set.
Click "inspect" to evaluate.
// The 146 contract:
// 1. Classify request initiator and target by IP address space (public / private / local).
// 2. If target's space is "more private" than initiator's → kick off a CORS preflight tagged
// with Access-Control-Request-Private-Network: true.
// 3. Server MUST reply with Access-Control-Allow-Private-Network: true (alongside normal CORS
// Allow-Origin and Allow-Methods) within a secure context.
// 4. From 146, even a stored permission isn't enough on its own — a missing PNA header still blocks.