The request pipeline is the ordered set of steps a web server uses to process an incoming request, apply logic, and return a response. It may include authentication checks, routing, middleware, modules, rewrites, logging, and content generation. Each stage can inspect or modify headers, cookies, paths, and response data before the page reaches the client.
In cyber security, the request pipeline matters because attackers who gain server-side control can insert code at any stage and silently change what different visitors see. That can enable redirects, malware delivery, SEO fraud, session theft, or selective content injection that affects only crawlers or specific user agents. Defenders look for unusual modules, unexpected rewrites, and response differences between normal browsers and automated scanners. Reviewing the pipeline helps reveal web implants and other tampering that basic file checks may miss.