Administrator utilities

HTTP/3 Check

Verify that a website actually responds over HTTP/3, with the negotiated protocol and response status.

Check All utilities

QUIC connection

Check HTTP/3 support

Enter a hostname or IP address and the HTTPS port.

QUIC

Check result

Targetforcevps.com

ProtocolHTTP/3

Port443

Not checked

Enter a target and run the check.

FAQ

What does HTTP/3 Check actually test?

The tool sends an HTTPS request from a ForceVPS network node and checks whether HTTP/3 was negotiated. It reports the connection result and response code, not merely the presence of an Alt-Svc header.

How does HTTP/3 differ from HTTP/2?

HTTP/3 runs over QUIC and normally uses UDP, while HTTP/2 normally runs over TCP. A successful HTTP/2 response does not by itself confirm HTTP/3 support.

Why does an Alt-Svc header not guarantee HTTP/3?

Alt-Svc only advertises that an alternative protocol may be available. If the UDP port is blocked or a QUIC connection cannot be established, an actual HTTP/3 request will not succeed.

What does an HTTP 404 or 500 response mean?

It is an application response code, not automatic proof that HTTP/3 is unavailable. Check the negotiated protocol to determine support; the requested page may still return an error.

Why does an IPv6 check time out?

An IPv6 request needs a working IPv6 address and route on the checking node plus access to the target UDP port. QUIC filtering along the path or unavailable HTTP/3 on the server can also cause a timeout.