JWT Decoder & Analyzer

Understand, Decode & Analyze JWT Tokens

The JWT Decoder & Analyzer gives you instant insight into the structure and content of any JSON Web Token. Whether you’re working with APIs, Single Sign-On (SSO), mobile apps, or penetration testing authentication flaws, understanding your JWT is crucial for both developers and bug bounty hunters.

• Auto-detects and decodes JWT header and payload in real time
• Checks for common algorithm risks (none, HS256, RS256...)
• Highlights expiration status, structure, and JSON pretty print
• Copy, share, and study JWTs securely without online storage

JWT Attack Surfaces and Security Insights

JWT vulnerabilities can allow privilege escalation, impersonation, or secret leaks. Look for "none" or weak symmetric algorithms, missing exp claims, or public information leaks. This tool is designed for ethical hacking, bug bounty, and secure API development—never use tokens on unauthorized systems.