HTTP/2
also: H2, HTTP2
HTTP/2 is a binary protocol and major revision of the HTTP web protocol that improves performance through multiplexing, server push, and header compression.
HTTP/2 is the second major version of the Hypertext Transfer Protocol, standardized in 2015 (RFC 7540). Unlike HTTP/1.1, which processes requests sequentially over individual connections, HTTP/2 allows multiple requests and responses to be sent simultaneously over a single connection through a technique called multiplexing.
Key improvements include: binary framing for efficient parsing, header compression using HPACK to reduce overhead, server push (allowing servers to proactively send resources), and stream prioritization. These features significantly reduce latency and bandwidth usage compared to HTTP/1.1.
HTTP/2 is widely supported by modern web servers (Nginx, Apache with mod_http2) and browsers. Most HTTPS connections now use HTTP/2 by default. For example, when you visit a modern website, your browser negotiates HTTP/2 during the TLS handshake using ALPN (Application Layer Protocol Negotiation).