Integrating DAST and SAST into DevSecOps for Continuous API Security

While APIs have long supported software development, their importance has surged with modern architectures like microservices, serverless, and AI-powered applications. APIs now serve as the core of application functionality and data flow—making their security an operational priority.

This growth has also expanded the attack surface. According to Akamai’s 2024 API Security Impact Study, 84% of organizations experienced an API security incident in the past year, underscoring the urgency of stronger API threat protection.

Yet many teams still treat API security as a post-deployment task—often only enforced at the gateway. This reactive mindset leaves gaps, especially when undocumented or deprecated endpoints—known as shadow and zombie APIs—go undetected.

To move from reactive to proactive, API security must be integrated throughout the software development lifecycle. This starts with discovery and inventory using both static application security testing (SAST) and dynamic application security testing (DAST). SAST identifies APIs in code, while DAST uncovers those active at runtime. You can’t protect what you can’t see. Doing this helps identify APIs, including shadow and zombie APIs, that you may have otherwise missed.  When used together, they provide a comprehensive and current view of your API landscape. Once you’ve identified all of your APIs, you can then use API Security to check them.

Since security tools can only test what they know exists, this dual approach is essential to ensure all APIs are covered. Embedding this visibility and validation into DevSecOps workflows helps you:

• Gain continuous visibility into all APIs, including undocumented, shadow, and zombie APIs. This visibility must go beyond static definitions. DAST plays a crucial role by identifying APIs based on real runtime behavior, uncovering unknown or forgotten endpoints that were never documented or have been deprecated but remain exposed.
• Detect and remediate API vulnerabilities earlier in the pipeline by integrating both SAST and DAST into your DevSecOps workflows. SAST identifies vulnerabilities in the source code before deployment, while DAST uncovers issues that arise in runtime environments—such as misconfigurations or logic flaws. By combining these approaches, you gain full coverage across the API lifecycle and ensure that issues are found and fixed long before they reach production.
• Prevent API threats through real-time protection and intelligent feedback loops. DAST plays a crucial role in this stage by continuously evaluating live API traffic to detect unexpected behaviors, unauthorized access attempts, and runtime misconfigurations. Combined with SAST and runtime monitoring, DAST enables you to uncover vulnerabilities that static analysis may miss and ensures your defenses remain aligned with real-world usage.

This post explores how to make that shift from treating API security from being treated as a separate, siloed activity to becoming an integrated and automated component of the DevSecOps lifecycle. This means embedding API security testing, including first identifying APIs with SAST and DAST, into every phase of development, so that discovery, validation, and protection are continuous, scalable, and aligned with the way your teams already build and deploy software.

With the right strategy, tools, and feedback mechanisms, your team can continuously protect APIs without slowing development velocity.

Why API Security Needs a Seat at the DevSecOps Table

Too often, API security lags behind the rest of your application security efforts. Even in mature DevSecOps environments, APIs remain underprotected. Their distributed, ephemeral nature makes them difficult to catalog, test, and monitor with traditional AppSec approaches. Many APIs are created, modified, or deprecated without clear documentation, leading to shadow and zombie APIs that remain exposed but untracked.

To uncover these hidden endpoints, organizations need a dual approach: SAST to analyze source code for defined APIs, and DAST to observe live traffic and runtime behavior. Without this combined effort, it’s impossible to ensure that all APIs are accounted for, and API security tools can only test what they know exists. Discovery through SAST and DAST isn’t just helpful, it’s foundational to securing your API surface.

APIs expose the business logic that attackers crave. Unlike web interfaces, APIs often reveal more than they protect: direct access to objects, unfiltered data, and improperly scoped access controls. This creates a unique and often underestimated set of risks.

Here’s why APIs are a unique risk:

• APIs often expose sensitive data and core business logic
• Many are undocumented or poorly versioned (hello, shadow APIs)

This makes APIs a favorite attack vector. OWASP API Top 10 vulnerabilities, like Broken Object Level Authorization (BOLA), Broken Object Property Level Authorization (BOPLA), Unrestricted Resource Consumption, and Unrestricted Access to Sensitive Business Flows, are notoriously difficult to detect without purpose-built tools.

To address these challenges, shift your mindset: treat APIs as critical software assets, not plumbing. Implement a discovery-first approach using specifically SAST and DAST tools that can continuously identify both known and unknown APIs across your environment and list all the discovered APIs in a single global API inventory. Use automated scans to detect common misconfigurations and insecure patterns, and prioritize remediation of high-risk endpoints.

Also, integrate API-specific threat modeling into your development process. Ask questions early: What data does this API expose? Who should have access to it? What could go wrong if a bad actor found it? Embedding these questions into the design phase improves your ability to apply least-privilege, strong authentication, and robust input validation from the start.

In short, API security in DevSecOps isn’t just about scanning. It’s about realigning your processes, your tools, and your mindset to reflect the way modern applications actually work.

How DAST Enhances API Security in DevSecOps Pipelines

Embedding API security into DevSecOps pipelines requires more than simply adding a scan at the end of a build. It demands a deliberate, layered strategy — one that aligns with how your teams already develop, test, and deploy software. The goal is to build security into each phase of the software development lifecycle, without disrupting developer velocity or overburdening AppSec teams.

Think of it as a continuum: You begin with visibility and control, then move to automated testing, then extend protection into production, and close the loop with intelligent feedback. Each step supports the next, and together, they create a security posture that can adapt as your application grows more complex.

Why DAST Complements SAST for API Security

While SAST gives you deep visibility into your code and design-level flaws, DAST reveals how APIs behave in the wild. DAST can spot issues that static analysis tools can’t see, like unexpected data exposure during API calls, or misconfigured authentication headers that are only evident when the API is running. Together, they provide layered protection: SAST prevents vulnerabilities from being introduced, while DAST catches what slips through before it’s exploited.

Here are four essential capabilities that will help you establish continuous API security within your DevSecOps pipelines, each grounded in automation, integration, and practical outcomes. These aren’t theoretical best practices. They are actions you can take today to secure APIs more effectively across your entire SDLC:

1. Discover APIs Automatically (and Continuously)

Securing APIs starts with knowing exactly what you have, both what’s documented and what’s lurking beneath the surface. Shadow and zombie APIs (those that are undocumented, outdated, or deprecated but still accessible) are among the most common and dangerous blind spots in modern environments.

These are often discovered through a combination of SAST, which scans source code and configuration files, and DAST, which analyzes live traffic and runtime behaviors to detect exposed endpoints that were missed or abandoned. By combining both perspectives, you get a fuller picture of what APIs are actually in use, not just what was intended.

You can’t secure what you can’t see. Your first move is establishing full API visibility across your environment:

• Use a combination of SAST and DAST to discover APIs defined in code and exposed during runtime, including undocumented, shadow, and zombie APIs
• Monitor CI/CD pipelines for new or changed APIs
• Integrate with gateways and traffic to correlate known vs unknown API activity

This allows you to establish an API inventory and track drift over time. By continuously comparing current API activity against your known inventory, you can detect when new, modified, or deprecated endpoints emerge. Doing so helps ensure you stay ahead of shadow APIs, unapproved changes, and security gaps introduced during rapid development cycles.

2. Embed API Security Testing into CI/CD

Once you’ve got visibility, the next step is automating API security testing directly into your DevSecOps pipelines:

• Use Checkmarx One to embed API security scans into CI/CD workflows
• Scan every build, not just major releases
• Run tests for OWASP API Top 10, business logic abuse, and schema violations

In addition to static code analysis, dynamic application security testing (DAST) plays a critical role in detecting vulnerabilities that only appear during runtime, such as authentication flaws, misconfigurations, and business logic errors. Checkmarx DAST helps you continuously test your running applications and APIs within staging or production-like environments, ensuring comprehensive coverage across all layers of API behavior.

This ensures APIs are validated at every stage of development and deployment. You can also fail builds automatically if critical vulnerabilities are found, enforcing compliance with your security gates. 

While some testing must happen later in the lifecycle, the goal should be to shift as much security validation as early as possible, ideally at the pull request or commit level. This approach catches issues when they are cheaper and faster to fix, and it helps maintain the pace of delivery without sacrificing protection.

3. Enable Real-Time API Security Monitoring

Some vulnerabilities only surface when APIs are in production.  DAST excels in finding APIs, while runtime testing uncovers how they act in real-world scenarios. That’s why API threat protection also means:

• Monitoring for anomalous traffic patterns, abuse, or abuse attempts
• Correlating runtime data with pre-production scans
• Integrating with SIEMs and threat intel to detect active exploitation

Always-on, real-time API security monitoring lets you spot issues before they become breaches. Combine this with Checkmarx’s API discovery and testing capabilities for full lifecycle coverage.

4. Build a Feedback Loop from Production to Dev

Securing APIs is never a one-and-done job. With continuous feedback loops:

• Production insights inform developer code changes
• New threat patterns update your security tests
• Fixes and coverage gaps are automatically flagged during code reviews

This aspect of DevSecOps automation helps your API security posture evolve with your application, rather than lagging behind it. Checkmarx supports this continuous improvement by enabling feedback loops that connect runtime data, developer activity, and security findings in one platform. This ensures that new risks are addressed as soon as they appear, not weeks or months later.

What Continuous API Security Looks Like in Practice

Continuous API security is most effective when it’s embedded throughout your SDLC, not just bolted on at the end. While many companies have successfully implemented DevSecOps practices for traditional application components, fewer have achieved full lifecycle API visibility and protection. This is where the real opportunity lies.

Organizations aiming to secure their API surfaces should begin by identifying where APIs are defined, discovered, and exposed, then map that to their current coverage with SAST and DAST tools. Gaps in API inventories or runtime testing often point to areas where shadow and zombie APIs may be lurking.

Use this insight to prioritize the integration of automated API discovery and testing at every phase, from code and CI/CD to runtime monitoring and feedback loops. That’s how you build scalable, real-time API security into your DevSecOps workflows.

API Security is a DevSecOps Imperative

If you’re serious about DevOps security, securing API endpoints must be part of your foundation. From code to cloud, DevSecOps automation allows us to:

• Discover and document every API
• Shift left with continuous API security testing
• Monitor runtime behavior and threats
• Automate remediation and policy enforcement

To begin, take stock of your current SDLC and identify where API security coverage is weak or missing altogether. Are API inventories current and complete? Are security tests run on every build and deployment? Are findings reaching developers in a way that drives action?

From there, prioritize investments that integrate seamlessly with your CI/CD pipelines and developer workflows. Focus on automation over manual review, shift-left testing over post-production patching, and data-driven feedback loops that help you adapt in real time.

You don’t have to start from scratch. With solutions like Checkmarx API Security as well as SAST and DAST on the Checkmarx One platform, you can embed this protection seamlessly across your SDLC and scale with confidence as your API surface grows.