SAST vs DAST vs (IAST/RASP): Quick AppSec Checklist

If you work in application security or do code reviews, you’ve probably heard the acronyms: SAST, DAST, IAST, RASP. They’re often mentioned together, but they solve different problems and fit into different stages of the SDLC.

Here’s a practical breakdown to help you choose the right tool for the job.

SAST (Static Application Security Testing)

• Analyzes source code or binaries without running the app
• Best used early in development (IDE, CI pipelines)
• Good for catching common issues like injection flaws, insecure logic, and misuse of APIs
• Trade-off: false positives and limited runtime context

DAST (Dynamic Application Security Testing)

• Tests a running application from the outside
• Works well against production-like environments
• Finds real, exploitable issues such as authentication flaws, misconfigurations, and runtime injection bugs
• Trade-off: limited visibility into the source code

IAST & RASP

• Run inside the application at runtime
• Combine code-level insight with real execution data
• Useful for high-confidence findings and production monitoring
• Trade-off: requires instrumentation and runtime overhead

So which one should you use?

There’s no single “best” option. Most mature security programs combine:

• SAST for early feedback

• DAST for real-world attack simulation

• IAST/RASP for runtime visibility and protection

I put together a concise secure coding and testing checklist that compares these approaches, explains where they fit best, and highlights common mistakes teams make when relying on only one tool.

👉 Secure Coding Practices Checklist
https://www.codereviewlab.com/learning/secure-coding-practices-checklist

If you’re doing code reviews, threat modeling, or building AppSec pipelines, it should save you time and help you pick the right tool for each phase.