API Scan Guide: How to Detect High-Severity Flaws in AI-Built Apps

Quick answer: An API scan is a security process that probes application endpoints for vulnerabilities like broken authentication, data leaks, and injection flaws. In SimplyScan's study of 182 AI-built apps, 11% had high-severity security issues. Automated scanning identifies these risks in vibe-coded projects, ensuring that AI-generated logic remains secure and compliant.

By Daniel A · Kraftwire Software

Why Is an API Scan Critical for AI-Built Applications?

When you build an application using "vibe-coding" tools like Lovable, Bolt.new, or Cursor, the speed of development often outpaces the implementation of security guardrails. An api scan is the only way to verify that the underlying logic generated by an AI agent actually respects data boundaries. Unlike traditional web scanning, which looks at the rendered UI, an API scan interacts directly with the endpoints that power your application.

In SimplyScan's scans of 182 AI-built apps, we found that 11% of these applications contained high-severity security issues. These are not minor bugs · they are critical flaws like exposed administrative keys or broken authentication that could lead to a total data breach. For developers using AI to generate full-stack code, the API is often the weakest link because the AI might prioritize "making it work" over "making it secure."

How Does Automated API Scanning Work for Developers?

Automated API scanning involves using tools to programmatically probe your endpoints for common vulnerabilities. For developers, this typically happens in two phases: design-time (conformance) and runtime (drift). A conformance scan tests whether your live API implementation matches your documentation, such as an OpenAPI or Swagger file.

Modern tools allow you to run these scans headless within a CI/CD pipeline. This ensures that every time your AI agent pushes a new feature, the API is automatically checked for regressions. According to industry research, a drift scan is specifically designed to monitor production APIs without being too invasive, ensuring that the live environment remains secure as the application evolves.

Key Components of an API Security Scan

• Endpoint Discovery: Identifying all active routes, including "shadow APIs" that the AI might have created but you didn't explicitly document.
• Fuzzing: Sending unexpected or malformed data to endpoints to see if they crash or leak information.
• Auth Testing: Verifying that protected routes actually require a valid security token and reject unauthorized requests.

What Are the Most Common API Flaws in Vibe-Coded Apps?

AI-built apps often suffer from specific architectural patterns that lead to security gaps. In SimplyScan's corpus of 182 scans, architecture issues appeared in 45% of the applications. These issues frequently manifest as broken object-level authorization (BOLA) or improper data filtering.

Broken Object-Level Authorization (BOLA)

This occurs when an API endpoint takes an ID (like /api/user/123) but fails to check if the person requesting the data actually owns that ID. An AI might generate a simple SELECT * FROM users WHERE id = $1 query without adding the necessary AND owner_id = $current_user clause.

Exposed Secrets and Keys

AI agents frequently place sensitive credentials directly into the frontend code or environment variables that are accidentally exposed. SimplyScan's secret scanner often detects OpenAI or Anthropic keys that should have been kept on the backend. This is a primary reason why 35% of scanned AI apps had at least one high or critical severity issue.

How to Scan an API for Vulnerabilities Manually?

While automated tools are essential, manual verification helps you understand the "why" behind a vulnerability. You can start by using a JWT debugger to inspect the tokens your API issues. If the token contains sensitive information in the payload or uses a weak signing algorithm, your API is at risk.

• Map your endpoints: List every URL your frontend calls.
• Test for IDOR: Change a resource ID in a request and see if you can access someone else's data.
• Check CORS settings: Ensure your API doesn't allow Access-Control-Allow-Origin: *, which could enable CSRF attacks.
• Validate Input: Send a string where a number is expected and look for verbose error messages that leak database structure.

Can You Automate API Scanning in Cursor or Windsurf?

Yes, developers using AI-native IDEs can integrate security scanning directly into their workflow. By using an MCP server, you can allow your AI agent to trigger scans and read the results without leaving the editor. This creates a feedback loop where the AI writes code, the scanner identifies a flaw, and the AI immediately fixes it.

For those using Windsurf or Cursor, the goal is to move security "left" in the development cycle. Instead of waiting for a production breach, you catch the 22% of medium-severity security issues identified in SimplyScan's data before the code is even committed.

What Is the Difference Between DAST and API Scanning?

Dynamic Application Security Testing (DAST) is a broad category that includes API scanning, but they focus on different layers. A standard DAST tool might crawl a website like a user would, clicking buttons and filling forms. An API scan, however, focuses on the "headless" interaction.

DAST Focus

• Cross-Site Scripting (XSS) in the browser.
• Broken links and UI-based redirects.
• Security headers like CSP and HSTS.

API Scan Focus

• JSON/XML injection.
• Rate limiting and DDoS protection.
• Logic flaws in the Supabase RLS or Firebase rules.

How Do You Fix High-Severity API Flaws?

Fixing a high-severity flaw usually requires more than a one-line code change; it often requires an architectural adjustment. If your api scan reveals that 11% of apps fail due to high-severity issues, you must prioritize these three fixes:

• Implement Strict RLS: If you are using a BaaS, ensure RLS policies are enabled for every single table. Never rely on the frontend to filter data.
• Rotate Exposed Keys: If a scan detects a leaked key, revoking it is the only solution. SimplyScan's exposed files tool can help identify where these leaks occur.
• Use a Gateway: Place your API behind a gateway that handles authentication, rate limiting, and logging centrally.

Why Does SimplyScan Focus on AI-Built Apps?

Traditional security tools are often too slow or complex for the "vibe-coding" movement. SimplyScan was built to provide a one-click security audit that understands the specific risks of AI-generated code. Whether you are building with Lovable, Bolt, or v0, the platform checks for the exact patterns that lead to the 86/100 average security score seen in our research.

One free scan on SimplyScan grades 8 dimensions in one pass · security, speed, SEO, AI visibility (AEO), accessibility (WCAG), GDPR/compliance signals, domain health and email security (SPF/DKIM/DMARC) · in ~30 seconds, no signup. It is the fastest way to perform an api scan and ensure your AI-built project is production-ready.

How to Maintain API Security Over Time?

Security is not a one-time event. As you add features, the attack surface of your API grows. Continuous monitoring is the only way to ensure that a new "vibe" doesn't introduce a critical regression.

• Scheduled Rescans: Use Pro Monitoring to automate rescans every week or after every major deployment.
• Uptime Monitoring: Ensure your API is not only secure but also available. Uptime monitoring helps you catch performance degradation before it affects users.
• Verified Badges: Once your app passes a scan, you can display a verified security badge to build trust with your users and stakeholders.

By integrating an api scan into your development routine, you protect your data and your reputation. In an era where AI can build an entire startup in a weekend, the only thing faster than development is the speed at which a vulnerability can be exploited. Don't let your app be part of the 35% with critical flaws. Scan it today.