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Pulseperformance

Modern HTTP

What This Audit Checks

This audit verifies that your page's resources are served over HTTP/2 or HTTP/3 rather than HTTP/1.1. It flags resources still delivered over HTTP/1.1, which lacks multiplexing, header compression, and server push capabilities.

Why It Matters

HTTP/1.1 limits browsers to six concurrent connections per origin. On a modern web page with dozens of resources, this creates a bottleneck where requests queue up waiting for a connection to become free. HTTP/2 multiplexes all requests over a single connection, and HTTP/3 (over QUIC) eliminates head-of-line blocking at the transport layer. Upgrading removes an artificial ceiling on your page load performance.

How to Fix It

  • Ensure your web server (Nginx, Apache, Caddy) or hosting platform has HTTP/2 enabled. Most modern servers support it out of the box with TLS, but it may need explicit configuration.
  • Verify your CDN serves HTTP/2 or HTTP/3. Major CDNs like Cloudflare, Fastly, and AWS CloudFront enable HTTP/2 by default and offer HTTP/3 as an opt-in.
  • Check third-party resources. If your analytics, font CDN, or ad scripts are served over HTTP/1.1, contact the provider or consider self-hosting those assets.
  • Enable HTTP/3 (QUIC) on your server or CDN if available. HTTP/3 is particularly beneficial for users on unstable mobile connections where packet loss causes HTTP/2 to stall.
  • Remove HTTP/1.1-era optimizations like domain sharding, sprite sheets, and CSS concatenation. These workarounds hurt performance under HTTP/2.

How Pulse Tracks This

Pulse checks the protocol version of every resource loaded during its Lighthouse audits and flags any still served over HTTP/1.1. The Modern HTTP card lists the affected URLs by origin so you can prioritize server upgrades.

Resources