Kiểm tra giao thức HTTP/2 miễn phí

It performs a live TLS handshake and reads the ALPN-negotiated protocol to confirm whether your server actually serves HTTP/2. It also reports the TLS version and whether HTTP/3 is advertised via the Alt-Svc header.

HTTP/2 is a major revision of HTTP that multiplexes many requests over a single connection, adds header compression (HPACK), and enables prioritization. It reduces round-trip overhead versus HTTP/1.1, speeding delivery of pages with many resources.

Over HTTPS, HTTP/2 is negotiated during the TLS handshake using ALPN (Application-Layer Protocol Negotiation). The client offers h2, and if the server agrees, the connection uses HTTP/2. This test reads exactly that ALPN result.

Enable the HTTP/2 module in your web server or CDN (for example the http2 directive in modern server builds) and ensure HTTPS with ALPN is active. HTTP/2 in browsers effectively requires TLS, so a valid certificate is prerequisite.

HTTP/1.1 sends requests largely one-at-a-time per connection and can suffer head-of-line blocking. HTTP/2 multiplexes concurrent streams over one connection and compresses headers, cutting latency for resource-heavy pages without opening many parallel connections.

No. HTTP/3 here is only inferred from the Alt-Svc response header, which advertises an h3 endpoint. This ALPN-based test confirms HTTP/2 directly but does not perform a QUIC handshake to prove HTTP/3 works.

The specification allows cleartext HTTP/2, but every major browser only supports it over TLS via ALPN. In practice you need a valid certificate and HTTPS for browsers to negotiate and use HTTP/2 at all.

TLS 1.3 is preferred for its faster handshake and stronger defaults, with TLS 1.2 as an acceptable minimum. HTTP/2's blocklist forbids obsolete ciphers, so modern TLS configuration avoids fallback to HTTP/1.1.

Confirm HTTPS with ALPN is enabled and the HTTP/2 module is on at whichever layer terminates TLS, often a CDN or reverse proxy rather than your origin. Some hosts serve HTTP/2 only at the edge.

It can reduce request overhead when a page loads many resources, but this protocol check does not measure page rendering or real-user speed. Compare field and browser measurements before attributing a speed change to HTTP/2.