JWT Security Analyzer

Not all JWTs are created equal. This security analyzer goes beyond simple decoding; it inspects your token for common vulnerabilities. It checks for "None" algorithm attacks, verifies that the "exp" (expiration) claim is present and valid, and analyzes the entropy of the signature. It provides a health report for your authentication tokens to help you prevent security breaches.
Vulnerability Detection Algorithm Validation Expiration Check Security Recommendations
SECURE
Protected Connection
Header.Payload.Signature
HS256, RS256, ES256
exp, iat, sub, aud validation
Trust Score
5.0
JWT Token Input
Enter a complete JWT token to analyze
Security Analysis Settings
Token Verification
Optional: Enter secret key to verify signature
Optional: Enter public key for signature verification
Quick Actions

Practical Applications & Use Cases

Vulnerability Assessment

Identify weaknesses in your authentication implementation.

  • Check for 'None' algorithm
  • Verify weak key usage
  • Audit missing claims
  • Validate time validity
Pro Tip: Ensure your production tokens are not using weak signing secrets that can be brute-forced.

Secure Implementation

Build security best practices into your auth system from day one.

  • Validate claim structure
  • Check audience (aud) mismatch
  • Verify issuer (iss) trust
  • Test token replay risks
Pro Tip: Always enforce a short expiration time combined with a refresh token mechanism.

Compliance & Standards

Ensure tokens meet industry standards (NIST/OWASP).

  • Verify strong algorithms (RS256)
  • Check scope granularity
  • Audit information leakage
  • Review payload size
Pro Tip: Avoid putting sensitive PII (Personally Identifiable Information) directly into the token payload.

Industry-Specific Applications

cybersecurity:

Penetration testing, security auditing, risk assessment

fintech:

PSD2 compliance, secure banking APIs, transaction signing

healthcare:

HIPAA compliant auth, patient data access, secure messaging

Help & Related Tools

Everything you need to know

FAQ Frequently Asked Questions

What security features does the JWT Security Analyzer provide?
The tool offers comprehensive JWT security analysis including algorithm validation, expiration checking, signature verification, vulnerability detection, claims analysis, and detailed security recommendations. Perfect for identifying common JWT security issues and implementation problems.
How do I analyze my JWT token for security vulnerabilities?
Simply paste your JWT token into the input field and click "Analyze JWT Token". The tool will automatically decode the token, check for security issues, validate algorithms, and provide detailed recommendations for improving token security.
Is the JWT Security Analyzer safe to use with production tokens?
Yes, all analysis happens entirely in your browser with no external API calls or data transmission. Your JWT tokens never leave your device, ensuring complete privacy and security during analysis.
What JWT algorithms and token types are supported?
The analyzer supports all standard JWT algorithms including HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, and can identify security issues with unsupported or weak algorithms like "none" or deprecated hash functions.
Can I export the security analysis results?
Absolutely! Export comprehensive security reports in Markdown format, copy decoded token sections, and download detailed analysis including vulnerability findings, claims validation, and security recommendations for documentation and compliance purposes.

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