Should I start with DAST or SAST?

Most 20-engineer orgs should start with SAST in CI (Snyk Code or Semgrep) because it costs nothing in the engineer time it saves.

Can one tool do both?

Invicti and Acunetix do DAST plus some IAST. Snyk does Code (SAST) but not DAST. Burp does DAST. There is no genuinely best-of-breed both-in-one.

Is IAST a third category?

Yes. Interactive Application Security Testing instruments the running app like an agent and reports issues with source-line evidence. AcuSensor is the most common.

Which finds OWASP Top 10 better?

DAST surfaces the runtime-observable Top 10 items reliably (injection, auth, misconfig). SAST surfaces the source-line equivalents but with higher false-positive rates.

No. Snyk Code is SAST only. For DAST coverage pair it with Burp, Invicti, Acunetix, or ZAP.

// taxonomy

DAST vs SAST: what each catches that the other misses

Dynamic Application Security Testing scans a running app from the outside. Static Application Security Testing scans source code before it runs. Different bugs, different lifecycle stages.

author: Oliver Wakefield-Smith · verified 2026-06-26

// direct-answer

What is the difference between DAST and SAST?

DAST (Dynamic) probes a running web app from the outside, finding runtime issues like injection, auth bypass, and misconfiguration. SAST (Static) parses source code pre-compile, finding source-pattern bugs like insecure cryptographic usage, hard-coded credentials, and SQL string concatenation. They catch different bugs and belong at different lifecycle stages.

DAST

Runtime, black-box. Catches what SAST cannot see: authentication flow bypass, session handling, server config, business logic gaps surfaced via traffic patterns.

Tools: Burp Enterprise, Invicti, Acunetix, OWASP ZAP, Nuclei

SAST

Pre-compile, white-box. Catches what DAST cannot see: source-line bugs in dead-code paths, hard-coded secrets, weak crypto API usage, taint analysis from input to sink.

Tools: Snyk Code, Checkmarx, SonarQube, Semgrep

PCI DSS 6.6 alignment

PCI DSS 6.6 lets you choose: a WAF in front of public web apps, OR an annual application code review / scan. DAST or SAST both satisfy the scan path; most QSAs prefer DAST output as the audit-acceptable artifact.

[PCI SSC ↗]

// faq

FAQ

Should I start with DAST or SAST?
Most 20-engineer orgs should start with SAST in CI (Snyk Code or Semgrep) because it costs nothing in the engineer time it saves.
Can one tool do both?
Invicti and Acunetix do DAST plus some IAST. Snyk does Code (SAST) but not DAST. Burp does DAST. There is no genuinely best-of-breed both-in-one.
Is IAST a third category?
Yes. Interactive Application Security Testing instruments the running app like an agent and reports issues with source-line evidence. AcuSensor is the most common.
Which finds OWASP Top 10 better?
DAST surfaces the runtime-observable Top 10 items reliably (injection, auth, misconfig). SAST surfaces the source-line equivalents but with higher false-positive rates.
Does Snyk Code DAST?
No. Snyk Code is SAST only. For DAST coverage pair it with Burp, Invicti, Acunetix, or ZAP.

Related: Web app scanners Invicti Snyk