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Connectivity

HTTP(S) Check

Test a website or API endpoint quickly and inspect status, redirects, and TLS.

🌐

HTTP(S) Check

http

Input

  • Target: domain or URL (for example example.com or https://example.com).

What it checks

  • Final URL and status code.
  • Response time, broken down into DNS, TCP, TLS, request, time to first byte, and transfer.
  • HTTP protocol version, plus whether HTTP/3 is actually supported rather than only advertised.
  • IPv4 and IPv6 reachability, measured separately.
  • Security headers, graded A-F.
  • Server and content type (if available).
  • Redirect chain.
  • TLS certificate summary for HTTPS endpoints.

Tips

  • Use a full URL if you want to test a specific path.
  • Check the redirect chain when a status code looks unexpected.
  • In the timing breakdown, a large DNS figure points at the resolver, a large TLS figure at certificate or handshake cost, and a large time to first byte at the server itself.
  • A reused connection has no DNS or TCP phase, which is why those lines can be absent.
  • HTTP/3 is probed directly, because browsers and apps often negotiate HTTP/2 until they have seen the server advertise HTTP/3 once.
  • If HTTP/3 is advertised but the probe fails, UDP port 443 is probably blocked on your network rather than missing on the server.
  • Published IPv6 that does not connect is worth fixing: clients that prefer IPv6 stall before falling back, which users experience as a slow first load.
  • Security header grading ignores HSTS on plain HTTP, and accepts a Content-Security-Policy frame-ancestors directive in place of X-Frame-Options.

Deeplink

netdebug://http?target=https://example.com/api/health

Tip: in the app, open the Export menu (the share icon) on this screen and choose Copy Deeplink to copy this link as a Universal Link with your current target and options already filled in.