Knowledge of application security testing methodologies including Static Application Security Testing (SAST), Dynamic Application Security Testing (DAST), Software Composition Analysis (SCA), secrets detection, container security scanning, and Infrastructure as Code (IaC) security testing. Knowledge of package management ecosystems (e.g., npm, pip, NuGet, Maven, Gradle) and software supply chain security concepts including dependency management, lock files, transitive dependencies, Software Bill of Materials (SBOMs), and package integrity.