Knowledge Base

HTTP/2 Performance Overview

HTTP/2 introduces several protocol-level improvements that dramatically reduce latency and increase throughput compared to HTTP/1.1. Understanding these enhancements helps you design faster, more efficient web applications.

Key Features

  • Binary Framing: Simplifies parsing and reduces errors.
  • Multiplexing: Multiple requests/responses share a single connection.
  • Header Compression (HPACK): Reduces overhead for repetitive header fields.
  • Server Push: Proactively sends resources the client will need.
  • Stream Prioritization: Allows fine‑grained control over resource delivery order.

Performance Benefits

By removing head‑of‑line blocking and enabling parallelism, HTTP/2 can cut page load times by up to 50 % on high‑latency networks. Below is a concise summary of typical gains:

MetricHTTP/1.1HTTP/2Improvement
Requests per connection1 – 6 (often 2 – 4)Unlimited (multiplexed)↑
Header size per request≈ 800 B≈ 200 B (compressed)↓
Round‑trip latency2 × RTT per request1 × RTT (multiplexed)↓
Page load (mobile, 3G)4.2 s2.3 s45 %

Best Practices

  1. Serve assets over HTTPS – browsers only support HTTP/2 on TLS.
  2. Enable server push for critical resources (e.g., CSS needed for above‑the‑fold content).
  3. Combine small assets when appropriate, but avoid large monolithic bundles; use prioritization.
  4. Leverage modern TLS settings (ALPN, TLS 1.3) to reduce handshake overhead.
  5. Monitor performance with real‑user metrics (LCP, FID, CLS) to validate gains.

Further Reading