Explore the evolution of web browser security in this comprehensive conference talk from NDC Oslo 2024. Discover how modern browsers have transformed from being the primary security risk to becoming the last line of defense against web attacks. Delve into the various security mechanisms and APIs integrated into browsers over the past decade, learning how they protect websites from common threats, provide enhanced authentication functionality, and reduce the attack surface by imposing browser restrictions. Through code-heavy demonstrations, examine the effectiveness of these security features in neutralizing dangerous attacks and understand the simplicity of implementing additional security layers. Gain insights into upcoming security developments and identify which functionalities are slated for deprecation, equipping yourself with essential knowledge to fortify web applications against evolving threats.