Security is all about defense in depth: applying layer upon layer of security controls such that any one single failure does not lead to a compromise of the application. One of those layers is the browser itself, which is becoming increasingly intelligent when it comes to implementing defenses. Security headers are a way of telling the browser how a website may behave when it’s loaded into the client. They provide numerous defenses against a variety of attacks in ways that have not previously been possible with security controls that ran solely on the server. In this course, we’ll walk through a number of essential security headers that provide even greater levels of defense for web applications. We’ll look at how they’re intended to work, what attacks they protect against, and how you can easily implement them in your website.