# HTTP/2 and HTTP/3 — Web Performance Optimization

Source: https://www.geekswithgeeks.com/en/web-performance/web-perf-07

> Modern protocols that improve performance through multiplexing, header compression, and faster handshakes.

## HTTP/2 multiplexing

HTTP/2 sends multiple requests over one connection simultaneously. No need to bundle assets or domain sharding. Header compression (HPACK) reduces overhead. Automatic prioritization of critical resources.

## HTTP/3 and QUIC

HTTP/3 uses QUIC (UDP-based) instead of TCP. Faster connection establishment (0-RTT resumption), better loss recovery. Particularly beneficial for high-latency and mobile networks.

## Protocol adoption timeline

HTTP/1.1 (obsolete), HTTP/2 (96% browser support), HTTP/3 (growing but not universal). Check your server/CDN support. Most modern CDNs support both HTTP/2 and HTTP/3.

Quick check

**Quiz:** What is a key advantage of HTTP/3?

- [ ] Uses UDP instead of TCP for faster handshake
- [ ] Smaller file sizes
- [ ] No compression needed