JavaScript Security Scanner — Detect JS Vulnerabilities Instantly
Scan JavaScript code for common security vulnerabilities with a free, client-side static analysis tool. Detects OWASP Top 10 issues including XSS, injection flaws, hardcoded secrets, and insecure patterns.
AI Code Security Scanner
Paste JavaScript or TypeScript code and scan for common security vulnerabilities. Detects hardcoded secrets, injection flaws, XSS, SSRF, prototype pollution, and more. 100% client-side — your code never leaves your browser.
OWASP Top 10 vulnerabilities in JavaScript
The OWASP Top 10 lists the most critical web application security risks. In JavaScript applications, the most common are: A01 Broken Access Control (missing authorization checks), A02 Cryptographic Failures (weak hashing, insecure randomness), A03 Injection (SQL, command, NoSQL injection via string concatenation), A04 Insecure Design (missing rate limiting, open redirects), A07 Cross-Site Scripting (innerHTML, document.write, dangerouslySetInnerHTML). This scanner checks for patterns associated with each of these categories.
Client-side vs server-side JavaScript security
Client-side JavaScript faces XSS, prototype pollution, and DOM manipulation risks. Server-side Node.js faces injection, path traversal, SSRF, and command execution risks. This scanner covers both contexts — it detects innerHTML and document.write() (browser-specific), as well as exec(), readFile(), and database queries (server-specific). Paste any JavaScript code and get a comprehensive security assessment.
JavaScript-specific security patterns
JavaScript has unique security concerns: eval() and new Function() enable arbitrary code execution, prototype pollution through bracket notation can bypass security checks, Math.random() is predictable and should never be used for security, template literals with ${} in database queries enable injection, and the dynamic typing system can be exploited for type confusion attacks. This scanner checks for all of these patterns with specific fix recommendations.
Frequently Asked Questions
What JavaScript vulnerabilities does this scanner detect?
The scanner detects 20+ vulnerability patterns: hardcoded secrets and API keys, SQL/NoSQL/command injection, XSS via innerHTML and dangerouslySetInnerHTML, SSRF with user-controlled URLs, path traversal in filesystem operations, prototype pollution, eval() and new Function(), insecure cookies, CORS misconfigurations, weak hashing, JWT decode without verify, open redirects, and more.
Does this work for TypeScript code?
Yes. TypeScript is a superset of JavaScript, so all JavaScript security patterns apply. The scanner analyzes the code as text — it works equally well with .js and .ts files, including React/JSX/TSX components.
How accurate is regex-based security scanning?
Regex-based scanning catches common vulnerability patterns with high precision but can produce false positives (flagging safe code) and false negatives (missing complex vulnerabilities). It excels at finding hardcoded secrets, obvious injection patterns, and known antipatterns. For data flow analysis, use a full SAST tool like Semgrep or CodeQL.
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