HTTP/2 & HTTP/3 test
See which modern HTTP protocols your server negotiates.
This HTTP/2 test and HTTP/3 test connects to your server and reports which protocol version it negotiates, and whether it advertises the QUIC-based HTTP/3 transport. Modern protocols deliver multiplexed connections, header compression, and lower latency, so confirming support tells you whether visitors get those gains. A result showing only HTTP/1.1 suggests your server or CDN is not configured to advertise the newer versions. Since a proxy or CDN tweak can silently change this, it's worth re-checking after changes.
Frequently asked questions
What's the benefit of HTTP/2 and HTTP/3?
HTTP/2 multiplexes many requests over one connection and compresses headers, while HTTP/3 runs over QUIC to reduce latency and survive network changes. Both improve real-world page speed.
Why does my site only show HTTP/1.1?
Usually the web server, load balancer, or CDN is not configured to advertise newer protocols via ALPN. Enabling them at the edge typically resolves it.
How is HTTP/3 detected here?
HTTP/3 is detected from the Alt-Svc header the server sends to advertise an h3 endpoint — the standard signal browsers use to upgrade to QUIC on the next visit.
Do I need HTTP/3 if I already have HTTP/2?
It is not required, but HTTP/3 helps most on lossy or mobile networks where QUIC recovers faster than TCP. Many CDNs enable it with a single toggle.
Can protocol support change without my knowledge?
Yes, often through a CDN or proxy update. Re-checking after infrastructure changes catches a protocol that quietly stopped being offered.
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