HTTP/2 Checker

HTTP/2 is the most significant update to the HTTP protocol since 1997, when HTTP/1.1 was published by the IETF. As the web continues to grow exponentially, this new protocol addresses the need for enhanced efficiency, speed, and security. Supported by most modern web browsers, HTTP/2 is a critical upgrade for developers and website owners aiming to optimize their web performance.

Key Features of HTTP/2:

• Binary Protocol: Unlike HTTP/1.1, HTTP/2 is binary instead of textual, which improves processing speed and reduces errors.
• Full Multiplexing: It allows multiple requests to be sent in parallel over a single TCP connection, reducing latency and improving load times.
• Header Compression (HPACK): This feature reduces overhead by compressing headers, which is particularly beneficial for mobile networks and devices with limited bandwidth.
• Server Push: Servers can now "push" responses proactively into client caches, reducing the need for repeated resource requests and speeding up page load times.
• ALPN Extension: HTTP/2 uses the Application-Layer Protocol Negotiation (ALPN) extension to establish faster encrypted connections, determining the application protocol during the initial connection phase.
• Reduced Round Trip Times (RTT): With fewer RTTs, your website loads faster, even without additional optimization techniques.
• Elimination of Domain Sharding and Asset Concatenation: These techniques are no longer necessary, simplifying your web infrastructure.

For a detailed list of browsers that support HTTP/2, visit caniuse.com.

Why Migrate to HTTPS?

While this test can check both HTTP and HTTPS, it's important to note that most browsers support HTTP/2 only over HTTPS. To fully benefit from HTTP/2's performance enhancements, migrating to HTTPS is essential.

SPDY and HTTP/2:

This test does not directly verify SPDY but does check which TLS extension is supported for protocol negotiation. The tested extensions include either NPN or ALPN. While NPN was part of the SPDY protocol, it has been deprecated in favor of ALPN, which is now the standard approved by the IETF (RFC7301). ALPN, unlike NPN, reverses the protocol advertising process from the client to the server.

How to Test HTTP/2 via Command Line:

To test HTTP/2 using the command line, download the latest version of curl and run the following command:

curl --http2

By understanding and implementing HTTP/2, you can significantly enhance your website's performance, providing a faster and more secure experience for your users.