JWT Decoder & Debugger

Decode and debug JSON Web Tokens (JWT). View header, payload, and signature with formatted output.

All processing happens in your browser

What is a JWT?

  • 🔑 JSON Web Token: Secure way to transmit information between parties
  • 📦 3 Parts: Header (algorithm), Payload (data), Signature (verification)
  • 🔐 Encoded: Base64 encoded, NOT encrypted (data is readable)
  • ✅ Use Cases: Authentication, Authorization, Information Exchange
  • ⚠️ Security: Never store sensitive data in payload - it's not encrypted!
Standard JWT Claims Reference

iss

Issuer - who created the token

sub

Subject - whom the token refers to

aud

Audience - who should accept the token

exp

Expiration - when token expires

nbf

Not Before - when token becomes valid

iat

Issued At - when token was created

jti

JWT ID - unique identifier

Frequently Asked Questions

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