HTTP Headers: The First Line of Defense for APIs and Frontends 🇺🇸

Server-side security like authentication and data validation is crucial, but we often overlook the browser’s role as the final line of defense. HTTP security headers act as firewall rules for the client by dictating which resources are trusted and how they should be isolated.

In this session, we will explore the essential headers every modern application should ship, including CSP, CORS, and advanced isolation policies like COOP and COEP. Using concrete examples with Symfony and API Platform, you will learn how to build a robust security policy that protects your users against XSS, clickjacking, and side-channel attacks.