Make sure your website or web application users get content updates right now with minimal latency. This concise guide shows you how to push new data from the server to clients with HTML5 Server-Sent Events (SSE), an exceptional technology that doesn't require constant polling or user interaction. You'll learn how to build a real-world SSE application from start to finish that solves a demanding domain problem. You'll also discover how to increase that application's desktop and mobile browser support from 60% to 99%, using different fallback solutions. If you're familiar with HTML, HTTP, and basic JavaScript, you're ready to get started. Determine whether SSE, WebSockets, or data pull is best for your organization Develop a working SSE application complete with backend and frontend solutions Address error handling, system recovery, and other issues to make the application production-quality Explore two fallback solutions for browsers that don't support SSE Tackle security issues, including authorization and "disallowed origin" Develop realistic, repeatable data that's useful in test-driven SSE design Learn SSE protocol elements not covered in the example application