Learn about essential HTTP security headers for web applications in this comprehensive conference talk from NDC London 2021. Explore the fundamentals of HTTP headers and their role in web security. Dive deep into specific security headers like HTTP Strict Transport Security (HSTS), Content Security Policy (CSP), and X-Frame-Options (XFO). Understand their purposes, implementation methods, and see live demonstrations of their effects. Discover the importance of HTTPS, protection against Cross-Site Scripting (XSS), and browser sniffing. Gain insights on retrofitting security headers to existing applications, testing your website's security, and find valuable resources for further learning. Equip yourself with the knowledge to enhance the security of your web applications through effective use of HTTP headers.