Free Application Security Testing Tools (No Trial)

You can assemble a credible application security testing pipeline entirely from free and open-source tools, no trial downloads required. The trick is to cover four categories deliberately: static analysis, dynamic analysis, dependency analysis, and secret scanning. Each finds a different class of problem, and skipping one leaves a predictable gap.

Can you really do application security testing for free?

For a large share of it, yes. Mature open-source tools exist in every major category, and the main source-hosting platforms bundle free dependency and secret-scanning features. Free tooling asks more of you in assembly, tuning, and reporting than a commercial platform does, but the underlying detection can be excellent. A sensible path is to start free and spend money only where a specific, measured gap justifies it.

What are the main categories of AST tools?

• SAST (Static Application Security Testing) reads your source code for vulnerable patterns before it runs.
• DAST (Dynamic Application Security Testing) tests a running application from the outside, the way an attacker would.
• SCA (Software Composition Analysis) finds known-vulnerable third-party and open-source dependencies.
• Secret scanning catches credentials and keys that have been committed to code.

A reasonable program covers all four, because each catches something the others miss.

What are some well-known free SAST and DAST tools?

On the static side, Semgrep is a widely used open-source analyzer with a large community rule set that runs locally and in CI. For dynamic testing, OWASP ZAP is the best-known free web-application scanner, maintained as an open-source project. Both are actively developed and broadly adopted. As always, confirm the current license and edition terms before you standardize on any tool, since those can change.

How do I find vulnerable dependencies and leaked secrets for free?

These two categories are where free tooling delivers the most value fastest.

• Dependencies: Trivy scans projects and container images for known-vulnerable components, and Dependabot raises alerts and update pull requests on supported repositories.
• Secrets: Gitleaks and TruffleHog scan code and its history for committed credentials and keys.

Running one SCA tool and one secret scanner closes two of the most common and highest-impact gaps most teams have.

Should free tools run in CI/CD?

Yes, and this is where the value compounds. A scanner that runs on every change catches far more than one you remember to run occasionally.

• Wire SAST, SCA, and secret scanning into your pull-request and build pipeline so issues are caught before merge.
• Schedule DAST against test environments rather than production.
• Start by failing builds only on high-confidence, high-severity findings to avoid alert fatigue, then tighten the thresholds as the team adapts.

Putting it together

A free stack of a SAST tool, a DAST scanner, an SCA tool, and a secret scanner, all wired into CI, gives you meaningful coverage at zero license cost. Spend your budget on the gaps that remain, not on the baseline you can build for free.