A small team should usually start with dependency scanning and SAST on pull requests, add DAST against staging once the app is stable, and consider IAST only when test coverage and runtime support are in place. Order by effort and signal, not by what sounds most advanced.
Start from constraints, not features
Small teams have three scarce things: time, people who can triage, and patience for noise. The right first tool is the one that gives a clear signal with the least setup and the least ongoing attention.
Step 1: know your dependencies
Most applications are mostly other people's code. Before buying anything for first party code, get a software bill of materials and scan it for known vulnerabilities. It is quick, it needs no build changes in many setups, and the findings come with fix versions. This is not one of the three named in the question, but it often gives the biggest first win. Safeguard offers SBOM and dependency scanning with reachability analysis, and a free manifest check at gold.safeguard.sh/scan.
Step 2: SAST on pull requests
OWASP describes static tools as scalable and repeatable, reliably flagging well-known issues such as injection flaws with file and line detail. That suits a pull request check. Keep it narrow: new findings only, a short list of rules, and a named person to triage.
Be realistic about limits. OWASP also notes high false positive rates and weakness on authentication, access control and cryptography issues.
Step 3: DAST on staging
Once you have a stable staging environment, add a scheduled dynamic scan. The OWASP DevSecOps Guideline describes DAST as black-box testing that needs no source and little interaction once configured, which makes a nightly run realistic. It sees server configuration and input handling problems that static analysis cannot. Plan for authentication setup, which usually takes the most effort.
Step 4: IAST, maybe
IAST needs sensors inside the app and traffic from tests or testers. If you have strong automated tests and a supported runtime, it can add precise runtime findings. If not, the effort will not pay off yet.
Step 5: manual testing
The OWASP testing guide is clear that automated tools lack knowledge of your application and tend to miss custom business logic problems. At some point, add a manual review or penetration test for the flows that matter most, such as login, payments and permissions.
Rule of thumb
- One engineer, one product: dependency scan plus SAST on pull requests.
- A few engineers, staging environment: add DAST nightly.
- A platform team with mature tests: evaluate IAST.
Quick check
Do I need all three?
Not on day one. They find different things, so over time most teams add them in stages as capacity grows.
What is the cheapest first step?
Scanning your dependencies for known vulnerabilities, since it needs little setup and results usually include fix versions.
Sources
- Source code analysis tools, OWASP Community
- DAST, OWASP DevSecOps Guideline
- IAST, OWASP DevSecOps Guideline
- OWASP Web Security Testing Guide
- Free scan, Safeguard Gold
Last reviewed: 19 October 2026.
