About this tool
HTTP/2 checker
Detect HTTP/2 support through a real TLS ALPN negotiation
The online package provides the interface only; this website cannot execute this network query. Use the matching local runtime package with Node.js 20+, run node server.cjs, then open http://127.0.0.1:47831/en/index.html.
Built-in input example:
https://example.com
The ALPN negotiation result applies only to this server connection.
Frequently asked questions
What does this tool do?
Detect HTTP/2 support through a real TLS ALPN negotiation
How do I use this tool?
The online package provides the interface only; this website cannot execute this network query. Use the matching local runtime package with Node.js 20+, run node server.cjs, then open http://127.0.0.1:47831/en/index.html.
Which settings can I change?
There are no extra settings. Supply data using the input area shown on the page.
What should I check before using it?
The ALPN negotiation result applies only to this server connection.
The online package provides the interface only; this website cannot execute this network query. Use the matching local runtime package with Node.js 20+, run node server.cjs, then open http://127.0.0.1:47831/en/index.html.
Where is my input sent?
The local service sends query targets to the relevant public network, DNS or registration service. Private network addresses are not supported. External services may be unavailable or rate-limited.