Static Application Security Testing (SAST) works like an architectural blueprint review. It parses source code or bytecode statically to identify insecure regex patterns, hardcoded secrets, and SQL injection flaws during code review.
Dynamic Application Security Testing (DAST) functions like a live structural stress test. It transmits real HTTP/HTTPS requests against a running staging or production server to discover runtime flaws—such as authentication bypasses, broken session cookies, and cross-site scripting (XSS).
Common Misclassification: Tools like SonarQube are pure SAST code analyzers, not DAST tools. They cannot perform live server network scans or evaluate live cloud infrastructure behavior.