Tools / Site Analysis
HTTP/2 & HTTP/3 Check
See whether a server negotiates HTTP/2 and advertises HTTP/3, plus its TLS version
The lookup is made by our server against public DNS; only the domain/IP you enter is used.
About this tool
Check whether a server negotiates HTTP/2 through TLS ALPN, which TLS version it uses, and whether it advertises HTTP/3 through the Alt-Svc header. Modern protocols reduce latency, and TLS 1.3 is the current standard.