Continuous Application Security (CAS) is a methodology designed to integrate security into the rapid development environments of Agile and DevOps by transforming traditional security practices into "security as code." It addresses the challenges of delivering secure applications without slowing down development processes, using instrumentation-based security enforcement to enable development, security, and operations teams to collaborate effectively. CAS emphasizes continuous, automated, and real-time security measures to tackle the persistent vulnerability issues in applications, which remain a leading cause of data breaches. Key components of CAS include Interactive Application Security Testing (IAST) and Runtime Application Self-Protection (RASP), which provide real-time feedback and defense against attacks while allowing organizations to deploy new defenses without needing to rewrite code. By embedding smart sensors directly into applications, CAS facilitates seamless vulnerability analysis during the software development lifecycle, ensuring security is both proactive and integrated.