HTTP/2 Checker

HTTP/2 is the first major update to the HTTP protocol since HTTP/1.1 was introduced by the IETF in 1997. As internet usage continues to expand, HTTP/2 addresses the growing demand for enhanced efficiency, speed, and security. Supported by the majority of modern web browsers, HTTP/2 is a must-have upgrade for developers and website owners looking to improve their web performance and user experience.

Key Features of HTTP/2

• Binary Protocol: HTTP/2’s binary format replaces the textual format of HTTP/1.1, resulting in faster processing and reduced errors.
• Full Multiplexing: Multiple requests can be sent simultaneously over a single TCP connection, dramatically reducing latency and improving page load times.
• Header Compression (HPACK): HTTP/2 compresses headers, significantly decreasing overhead—especially beneficial for mobile users and networks with limited bandwidth.
• Server Push: HTTP/2 allows servers to "push" resources proactively into a client’s cache, minimizing repeated requests and accelerating load times.
• ALPN Extension: Application-Layer Protocol Negotiation (ALPN) enables faster encrypted connections by determining the application protocol during the initial handshake phase.
• Reduced Round Trip Times (RTT): Fewer RTTs mean faster page loads and improved performance, even without additional optimizations.
• Streamlined Infrastructure: HTTP/2 eliminates the need for complex techniques like domain sharding and asset concatenation, simplifying your web setup.

Curious about browser compatibility? Check out the detailed list of supported browsers at caniuse.com.

Why Migrate to HTTPS?

While HTTP/2 supports both HTTP and HTTPS, the majority of browsers only implement HTTP/2 over HTTPS. To unlock the full performance benefits of HTTP/2, upgrading to HTTPS is essential. Secure connections also boost user trust and align with SEO best practices, as search engines prioritize secure websites.

SPDY and HTTP/2: What You Need to Know

While this test does not directly validate SPDY, it checks for TLS extensions used during protocol negotiation, including NPN and ALPN. Although NPN was originally part of SPDY, it has been replaced by ALPN, which is now the IETF-approved standard (RFC7301). ALPN reverses the negotiation process, allowing clients to propose protocols to the server, enhancing performance and compatibility.

How to Test HTTP/2 via Command Line

Testing your site’s HTTP/2 implementation is easy with curl. Follow these steps:

1. Download the latest version of curl.
2. Run the following command in your terminal:

curl --http2

Evaluating your site’s HTTP/2 performance is the first step towards providing a faster, more secure user experience.

Ready to upgrade? Use our Uptime4 Tool to ensure your website is optimized for HTTP/2 today.