API Security
Last updated: January 16, 2026
API security vulnerabilities expose application data and functionality through improperly secured endpoints, missing authentication, or excessive data exposure.
Scan for This VulnerabilityWhat is API Security?
APIs are the backbone of modern applications, exposing functionality to frontends and third parties. Security failures include missing authentication, broken authorization, excessive data exposure, and lack of rate limiting. APIs are increasingly targeted as they provide direct data access.
Why It's Dangerous
This vulnerability can allow attackers to access sensitive data, compromise user accounts, or gain unauthorized control over your application. In AI-generated code, this issue is particularly common because security measures are often deprioritized in favor of rapid feature development.
Why AI Code Is Vulnerable
AI code generation tools focus on producing functional code quickly. They often generate patterns that work correctly but lack the defensive measures experienced security engineers would implement. This makes api security particularly prevalent in vibe-coded applications.
Understanding the Technical Details
API Security is classified as a high-severity vulnerability because of its potential to cause significant damage to your application and users. Understanding the technical mechanics helps you recognize and prevent this issue in your own code.
This vulnerability typically occurs when security controls are either missing entirely, improperly configured, or incorrectly implemented. In many cases, the code appears to work correctly during development and testing, but the security flaw becomes exploitable once the application is deployed and accessible to malicious actors.
Attackers actively scan for this type of vulnerability using automated tools. Once discovered, exploitation can be rapid—often within hours of your application going live. The consequences range from data theft and account takeover to complete system compromise depending on the application's architecture.
For vibe-coded applications built with platforms like Lovable, Bolt.new, Replit, or v0.dev, this vulnerability appears in roughly 20-40% of deployments according to security research. The AI-generated patterns often follow insecure defaults that require manual security hardening.
How It Happens
- Missing authentication on endpoints
- Broken object-level authorization
- Excessive data exposure
- Lack of rate limiting
- Missing input validation
- Verbose error messages
Impact
Data breaches
Unauthorized actions
Service abuse
Resource exhaustion
Business logic exploitation
How to Detect
- Audit all API endpoints
- Test authorization on each endpoint
- Check for overfetching
- Verify rate limiting
- Run VAS API security scan
How to Fix
Authenticate all sensitive endpoints
Require and verify authentication.
// Middleware to require auth
export function requireAuth(handler) {
return async (req, res) => {
const user = await getUser(req);
if (!user) {
return res.status(401).json({ error: 'Unauthorized' });
}
req.user = user;
return handler(req, res);
};
}
// Apply to routes
export default requireAuth(async (req, res) => {
// This only runs if authenticated
});Implement proper authorization
Check permissions for each operation.
// Check resource ownership
const document = await db.documents.findUnique({
where: { id: documentId }
});
if (document.userId !== req.user.id) {
return res.status(403).json({ error: 'Forbidden' });
}Return only required data
Don't overfetch or expose internal fields.
// BAD - returns everything including internal fields
return res.json(user);
// GOOD - explicit field selection
return res.json({
id: user.id,
name: user.name,
email: user.email,
// Don't include: password hash, internal IDs, etc.
});Commonly Affected Platforms
Prevention Best Practices
The most effective approach to api security is prevention. Implementing security measures during development is significantly easier and less costly than remediating vulnerabilities after deployment.
Security-First Development
When using AI code generation tools, always review the generated code for security implications. AI tools prioritize functionality over security, so treat all generated code as requiring security review. Establish a checklist of security requirements specific to your application type and verify each before deployment.
Continuous Security Testing
Integrate security scanning into your development workflow. Run scans after major code changes, before deployments, and on a regular schedule for production applications. Early detection of vulnerabilities reduces remediation costs and prevents potential breaches.
Defense in Depth
Never rely on a single security control. Implement multiple layers of protection so that if one control fails, others still protect your application. For example, combine authentication, authorization, input validation, and output encoding to create comprehensive protection against attacks.
Stay Informed
Security threats evolve constantly. Follow security researchers, subscribe to vulnerability databases, and monitor your dependencies for known issues. Understanding emerging threats helps you proactively protect your applications before attackers exploit new techniques.
Is Your App Vulnerable?
VAS automatically scans for api security and provides detailed remediation guidance with code examples. Our scanner specifically targets vulnerabilities common in AI-generated applications.
Scans from $5, results in minutes. Get actionable results with step-by-step fix instructions tailored to your stack.
Get Starter ScanFrequently Asked Questions
Should I use API keys or JWTs?
For user authentication: JWTs or session tokens. For service-to-service: API keys with proper scoping. JWTs can be verified without database lookups but can't be easily revoked. API keys require lookup but offer fine-grained control. Many apps use both for different purposes.
How do I rate limit my API?
Use rate limiting middleware (express-rate-limit, @upstash/ratelimit). Limit by IP for unauthenticated endpoints, by user ID for authenticated ones. Set sensible limits: maybe 100 requests/minute for normal use, stricter for auth endpoints. Return 429 Too Many Requests when exceeded.