HTTP/2 Checker

HTTP/2 represents the most significant evolution of the HTTP protocol since the introduction of HTTP/1.1 in 1997. Designed to meet the demands of a rapidly expanding web, HTTP/2 delivers enhanced efficiency, faster load times, and improved security. Supported by all major modern browsers, this upgrade is a must for developers and website owners who want to optimize their website’s performance.

Key Features of HTTP/2

• Binary Protocol: HTTP/2 uses a binary format instead of the textual format of HTTP/1.1, enabling faster processing and reducing potential errors.
• Full Multiplexing: Supports multiple simultaneous requests over a single TCP connection, minimizing latency and improving page load speeds.
• Header Compression (HPACK): Compresses HTTP headers to reduce bandwidth usage, particularly beneficial for mobile networks and devices with limited resources.
• Server Push: Allows servers to proactively send resources to the client cache before they are requested, further speeding up load times.
• ALPN Extension: Leverages the Application-Layer Protocol Negotiation (ALPN) extension to establish faster, encrypted connections by selecting the protocol during the initial handshake.
• Reduced Round Trip Times (RTT): Decreases the number of round trips required to load a webpage, ensuring faster delivery of content.
• Elimination of Domain Sharding and Asset Concatenation: Simplifies web infrastructure by removing the need for outdated optimization techniques.

For an up-to-date list of browsers supporting HTTP/2, visit caniuse.com.

Why Migrate to HTTPS?

While HTTP/2 supports both HTTP and HTTPS, most modern browsers enable HTTP/2 only over HTTPS. Migrating to HTTPS is essential to fully benefit from HTTP/2’s speed and security enhancements. Additionally, HTTPS ensures your site remains compliant with security best practices, protecting user data and building trust.

SPDY and HTTP/2

This test doesn’t directly verify SPDY but checks which TLS extensions are supported for protocol negotiation. These include NPN (deprecated) and ALPN. ALPN, introduced as part of HTTP/2 (RFC7301), is now the standard and replaces NPN. Unlike NPN, ALPN reverses the protocol negotiation process, allowing clients to advertise supported protocols to the server.

How to Test HTTP/2 via Command Line

To verify HTTP/2 support on your website using the command line, download the latest version of curl and execute the following command:

curl --http2 -I https://example.com

This command sends a GET request and displays the HTTP/2 headers returned by the server, giving you insights into how your server is configured.

Adopting HTTP/2 is a vital step in optimizing your website’s performance, ensuring faster, more secure, and modern web experiences for your users.