Application security testing is crucial to make sure your application is free of flaws and dangers, to minimize the attack surface, and to guard against online threats. Organizations today are under growing pressure to release secure, high-performing applications without slowing innovation, and this demands the right testing strategy that utilizes both efficiency and thoroughness.

Two of the most widely used approaches for AppSec are Dynamic Application Security Testing (DAST) and Static Application Security Testing (SAST). Both play critical roles in identifying vulnerabilities but they operate at different stages of development and uncover distinct types of risks.

This guide explores the difference between DAST vs SAST, their individual strengths, and how you can combine them to achieve comprehensive application security.

What is DAST (Dynamic Application Security Testing)?

Dynamic Application Security Testing (DAST) is a method of testing applications from the outside in. Often referred to as black-box testing, DAST evaluates a running application the same way an attacker would.

The goal of DAST is to identify and report on security issues that could be exploited by an attacker, so that they can be fixed before the application is deployed.

Instead of reviewing code, DAST interacts with the live application, sending various requests and inputs to identify security flaws that appear during runtime. This helps uncover real-world vulnerabilities like SQL injection, cross-site scripting (XSS), authentication weaknesses, and server misconfigurations.

DAST tools don’t require access to source code, which makes them ideal for testing compiled applications, APIs, or systems developed using multiple programming languages.

When to use DAST

You should use DAST when you need to understand how your application performs under real-world attack scenarios. Common use cases include:

• Pre-deployment testing: Before releasing an application, DAST helps validate that it’s secure from an external attacker’s perspective.
• Continuous monitoring in CI/CD pipelines: Many organizations integrate DAST into automated workflows to detect runtime vulnerabilities early and continuously.
• Third-party component testing: When working with externally built apps or APIs, DAST helps identify vulnerabilities even without code access.
• Regulatory compliance checks: DAST scans support frameworks like SOC 2, HIPAA, and ISO 27001, which require proof of security testing.

Benefits of using DAST

DAST delivers several important advantages that make it a cornerstone of modern AppSec programs:

• Real-world simulation: DAST tests the application’s behavior during actual execution, revealing vulnerabilities attackers can exploit in production.
• Language-independent: Since it tests compiled applications, DAST works with any language or framework.
• Comprehensive coverage: It identifies configuration issues, authentication weaknesses, and server misconfigurations that code analysis might miss.