# HTTP/2 and HTTP/3 Protocol Enhancements HTTP/2 and HTTP/3 are major revisions of the HTTP protocol, designed to address performance limitations of HTTP/1.x and improve security. ## HTTP/2 Enhancements HTTP/2 introduces a binary framing layer that is not present in HTTP/1.x. This allows for more efficient use of network resources and reduced perception of latency. ```javascript // HTTP/1.1 GET /index.html HTTP/1.1 Host: www.example.com // HTTP/2 [Stream 1] + HEADERS - GET www.example.com/index.html ``` HTTP/2 also implements Server Push, which enables the server to send multiple responses for a single client request, improving load times. ```javascript // Server Push in HTTP/2 PUSH_PROMISE - index.html HEADERS - :status 200 DATA - (index.html content) PUSH_PROMISE - style.css HEADERS - :status 200 DATA - (style.css content) ``` Furthermore, HTTP/2 supports Multiplexing, allowing multiple messages to be sent at the same time over a single TCP connection, reducing overhead. ## HTTP/3 Enhancements HTTP/3 replaces TCP with QUIC, a transport layer protocol developed by Google. QUIC aims to reduce latency by establishing multiple connections simultaneously. ```python # HTTP/2 TCP Handshake -> TLS Handshake -> HTTP/2 Stream # HTTP/3 QUIC Handshake (includes TLS) -> HTTP/3 Stream ``` HTTP/3 also introduces 0-RTT (Zero Round Trip Time Resumption) which enables a client to start sending data without waiting for a response from the server, further reducing latency. ```python # HTTP/3 0-RTT Client: ClientHello (with "early_data" extension) Server: ServerHello...[Finished] Client: ApplicationData (early data) Server: NewSessionTicket ``` Understanding these improvements in HTTP/2 and HTTP/3 can help software engineers optimize their applications for better performance and security.