HTTP/3 available
The request actually reached our HTTP/3 listener over QUIC/UDP. It confirms this protocol and destination, not unrestricted UDP support.
Proxy HTTP/3 & QUIC test.
See whether your browser connection supports HTTP/3 over QUIC. Open this page in the browser or proxy profile you want to test.
HOW TO USE THIS TEST
How to use this tool
Keep your usual proxy settings enabled. The endpoint advertises HTTP/3 and the browser gets several opportunities to use it.
- 01
Open the browser you want to test
The result describes this browser’s network path, including its proxy settings and protocol policy.
- 02
Request the protocol probe
The first request discovers the server’s HTTP/3 advertisement. Follow-up requests check whether the browser uses QUIC.
- 03
Read the actual protocol
An HTTP/3 response confirms QUIC for this endpoint. A TCP response or unreachable endpoint is reported separately.
What each result means.
Not observed
Requests reached the endpoint over TCP, but HTTP/3 was not used during the test. Browser settings, proxy support, or network policy may be responsible.
Unavailable
The endpoint could not be reached or the measurement service is not configured. This is missing evidence, not a UDP-blocked verdict.
PROXY HTTP/3 & QUIC TEST FAQ
Understand your results.
No single check proves whether a connection is direct. Read the signals together.
Does HTTP/3 use UDP?
HTTP/3 uses QUIC, which runs over UDP. This test counts HTTP/3 as available only when the QUIC listener actually serves the response.
Why does my SOCKS5 proxy work while HTTP/3 does not?
Working TCP proxy requests do not establish UDP support. The client, proxy server, upstream route, and network must support the required UDP path. Browser proxy implementations also differ in which protocols they route.
Is Not observed the same as UDP blocked?
No. A browser can choose TCP even when some UDP traffic is possible. The result only says that HTTP/3 was not observed during these requests.
Can QUIC work while the WebRTC check shows no address?
Yes. QUIC and WebRTC STUN are different protocols and can be handled differently by the browser, proxy, and firewall. Test them separately or run the full proxy checker for both results.