Traditional security tools like firewalls, WAFs, and vulnerability scanners are designed to protect your server infrastructure, but they can't see what's actually executing in your users' browsers. They monitor sanitized data, often slow down your site, or completely miss dynamic threats that change based on user location, device, or timing. Content Security Policies (CSPs) and JavaScript agents either see cleaned-up data or get bypassed by sophisticated attacks using techniques like CSP evasion, shadow-DOM tricks, and obfuscated code
Client-side attacks typically occur when a malicious actor compromises a third-party service your website uses.
Server-side security protects your infrastructure, while client-side security protects where your applications actually execute in users' browsers.
Client-side security is a critical subset of AppSec that focuses on protecting applications where they actually execute--in users' browsers.
Client-side security protects your website visitors from malicious JavaScript attacks that happen directly in their browsers.