demo · v142 · security

LNA Compliance Checker

Paste your JavaScript code below. The checker performs static analysis to find any fetch or XHR calls that target private/local network addresses — and tells you exactly which CORS headers your server must add to pass Chrome’s Local Network Access preflight.

Presets:

What Chrome 142 checks

When a public-origin page fetches a local/private address, Chrome sends a CORS preflight (OPTIONS) with the header Access-Control-Request-Private-Network: true. The server must respond with Access-Control-Allow-Private-Network: true — otherwise Chrome blocks the request.

Private address ranges

# RFC 1918 / private ranges Chrome considers "local network":
10.0.0.0/8         # Class A private
172.16.0.0/12      # Class B private
192.168.0.0/16     # Class C private (home routers)
127.0.0.0/8        # Loopback (localhost)
::1                # IPv6 loopback
fc00::/7           # IPv6 ULA
*.local            # mDNS / Bonjour

See also