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High Performance
Browser Networking

© Ilya Grigorik

Performance is a feature. This book provides a hands-on overview of what every web developer needs to know about the various types of networks (WiFi, 3G/4G), transport protocols (UDP, TCP, and TLS), application protocols (HTTP/1.1, HTTP/2), and APIs available in the browser (XHR, WebSocket, WebRTC, and more) to deliver the best—fast, reliable, and resilient—user experience.

Start Here: 2025 Reading Guide

This book was published in 2013. While the fundamental principles of network performance remain timeless, specific protocols and technologies have evolved. Before diving into the chapters, see the 2025 Reading Guide to understand which content is still directly applicable, which should be read for concepts, and how to supplement with modern protocols like HTTP/3 and QUIC.

View the 2025 Reading Guide →

§Table of Contents

Networking 101

  1. Primer on Latency and Bandwidth

  2. Building Blocks of TCP

  3. Building Blocks of UDP

  4. Transport Layer Security (TLS)

Performance of Wireless Networks

  1. Introduction to Wireless Networks

  2. WiFi

  3. Mobile Networks

  4. Optimizing for Mobile Networks

HTTP

  1. Brief History of HTTP

  2. Primer on Web Performance

  3. HTTP/1.X

  4. HTTP/2

  5. Optimizing Application Delivery

Browser APIs and Protocols

  1. Primer on Browser Networking

  2. XMLHttpRequest

  3. Server-Sent Events (SSE)

  4. WebSocket

  5. WebRTC

§About the author

Ilya Grigorik is a web performance engineer at Google and co-chair of the W3C Web Performance Working Group. Follow him on his blog and Twitter for the latest web performance news, tips, and talks.