Networking & DNS
Inspect DNS, MX, NS, WHOIS, ports, user agents, HTTP headers, and CORS from your browser
URL Parser
Parse a URL into scheme, host, port, path, query parameters, fragment, and origin — fully client-side
CIDR Calculator
Calculate network, broadcast, usable hosts, subnet mask, and wildcard for any IPv4 CIDR
User-Agent Parser
Parse a User-Agent string into browser, version, operating system, device type, and bot status
HTTP Header Inspector
Paste response headers to audit HSTS, CSP, CORS, X-Powered-By disclosure, and Set-Cookie flags
CORS Origin Checker
Test whether origins are allowed by a given Access-Control-Allow-Origin value — wildcard and subdomain aware
Well-Known Ports Reference
Searchable list of well-known TCP/UDP ports — filter by port number, service name, or description