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Documentation Core Tools Jwt Parser

Examples

This section provides practical examples of using the JWT Parser tool with different types of JWT tokens.

Basic JWT Example

Token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE1MTYyNDI2MjJ9.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

Parsed Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Parsed Payload

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022,
  "exp": 1516242622
}

Analysis

  • Algorithm: HS256 (HMAC with SHA-256)
  • Type: JWT
  • Subject: 1234567890
  • Name: John Doe
  • Issued At: January 19, 2018, 6:30:22 PM GMT
  • Expires: January 19, 2018, 7:30:22 PM GMT

Authentication Token Example

Token

eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2V4YW1wbGUuY29tIiwic3ViIjoiMTIzNDU2Nzg5MCIsImF1ZCI6Im15YXBwIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE1MTYyNDI2MjIsInJvbGUiOiJhZG1pbiIsInBlcm1pc3Npb25zIjpbInJlYWQiLCJ3cml0ZSIsImRlbGV0ZSJdfQ.EkN-DOsnsuRjRO6BxXemmJDm3HbxrbRzXglbN2S4sOkopdU4IsDxTI8jO19W_A4K8ZPJijNLis4EZsHeY559a4DFOd50_OqgH58ERTqYZyhtFJKh3ue6by8xcZMUd9J3d_VXaUeHy0yvaAffXYfTLQo6josBX6koFNo7cF8_IYfY1bCRXKgcS3mR8LS65lVmzuJmNF2UzP5k6N3k-jtd399gOmr9eWzE2LbUeqNfqpccX9xemRY9CP1JJs_76ejFk9FjCl79Z_0t1fYEE8NHmktoOgupIN_6eP59T0aH5nNtTpzV1mk_W7V3yJiqz0Nnp7dOfpW_VeaEj_1TqBj0

Parsed Header

{
  "alg": "RS256",
  "typ": "JWT"
}

Parsed Payload

{
  "iss": "https://example.com",
  "sub": "1234567890",
  "aud": "myapp",
  "iat": 1516239022,
  "exp": 1516242622,
  "role": "admin",
  "permissions": ["read", "write", "delete"]
}

Analysis

  • Algorithm: RS256 (RSA with SHA-256)
  • Issuer: https://example.com
  • Subject: 1234567890
  • Audience: myapp
  • Role: admin
  • Permissions: read, write, delete
  • Expires: 1 hour after issuance

API Access Token Example

Token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX2lkIjoxMjMsImVtYWlsIjoiam9obi5kb2VAZXhhbXBsZS5jb20iLCJzY29wZXMiOlsicmVhZCIsIndyaXRlIl0sImFwcF9pZCI6Im15YXBwIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE1MTYyNDI2MjJ9.4Adcj3UFYzPUVaVF43FmMab6RlaQD8A9V8wFzzht-KQ

Parsed Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Parsed Payload

{
  "user_id": 123,
  "email": "john.doe@example.com",
  "scopes": ["read", "write"],
  "app_id": "myapp",
  "iat": 1516239022,
  "exp": 1516242622
}

Analysis

  • User ID: 123
  • Email: john.doe@example.com
  • Scopes: read, write
  • App ID: myapp
  • Expires: 1 hour after issuance

Refresh Token Example

Token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX2lkIjoxMjMsInRva2VuX3R5cGUiOiJyZWZyZXNoIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE1MTY5NDM4MjJ9.7d_kzR8y0B1M2Z3N4O5P6Q7R8S9T0U1V2W3X4Y5Z6

Parsed Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Parsed Payload

{
  "user_id": 123,
  "token_type": "refresh",
  "iat": 1516239022,
  "exp": 1516943822
}

Analysis

  • User ID: 123
  • Token Type: refresh
  • Expires: 7 days after issuance (longer than access tokens)

Microservice Communication Token

Token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXJ2aWNlX2lkIjoiYXV0aC1zZXJ2aWNlIiwic2VydmljZV9yb2xlIjoiYXV0aGVudGljYXRvciIsInRhcmdldF9zZXJ2aWNlIjoiY29yZS1zZXJ2aWNlIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE1MTYyNDI2MjJ9.8f_kzR8y0B1M2Z3N4O5P6Q7R8S9T0U1V2W3X4Y5Z6

Parsed Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Parsed Payload

{
  "service_id": "auth-service",
  "service_role": "authenticator",
  "target_service": "core-service",
  "iat": 1516239022,
  "exp": 1516242622
}

Analysis

  • Service ID: auth-service
  • Service Role: authenticator
  • Target Service: core-service
  • Expires: 1 hour after issuance

Mobile App Token Example

Token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX2lkIjoxMjMsImRldmljZV9pZCI6ImRldmljZTEyMyIsImFwcF92ZXJzaW9uIjoiMS4wLjAiLCJwbGF0Zm9ybSI6ImlPUyIsImlhdCI6MTUxNjIzOTAyMiwiZXhwIjoxNTE2MjQyNjIyfQ.9g_kzR8y0B1M2Z3N4O5P6Q7R8S9T0U1V2W3X4Y5Z6

Parsed Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Parsed Payload

{
  "user_id": 123,
  "device_id": "device123",
  "app_version": "1.0.0",
  "platform": "iOS",
  "iat": 1516239022,
  "exp": 1516242622
}

Analysis

  • User ID: 123
  • Device ID: device123
  • App Version: 1.0.0
  • Platform: iOS
  • Expires: 1 hour after issuance

Error Examples

Invalid Format

invalid.jwt.token

Error: "Invalid JWT format. JWT should have 3 parts separated by dots."

Malformed JSON

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.invalid-json.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

Error: "Failed to parse JWT token"

Invalid Base64

invalid-base64.yyyyy.zzzzz

Error: "Failed to parse JWT token"

Usage Scenarios

Development Debugging

  1. API Testing: Parse tokens from API responses
  2. Authentication Flow: Debug authentication issues
  3. Token Validation: Verify token structure
  4. Claims Analysis: Check user permissions

Security Analysis

  1. Token Inspection: Examine token contents
  2. Expiration Monitoring: Check token lifetime
  3. Algorithm Verification: Confirm signing algorithm
  4. Claims Review: Analyze user data

Integration Testing

  1. Third-party APIs: Parse external service tokens
  2. Microservices: Analyze inter-service tokens
  3. Mobile Apps: Debug mobile authentication
  4. Web Applications: Test web authentication

Best Practices

Token Selection

  • Use Test Tokens: Always use test or development tokens
  • Avoid Production: Never use production tokens
  • Sensitive Data: Avoid tokens with sensitive information
  • Expired Tokens: Use expired tokens for testing

Analysis Workflow

  1. Load Token: Paste or load the token
  2. Review Structure: Check header and payload structure
  3. Analyze Claims: Review all claims and their values
  4. Check Expiration: Verify expiration time
  5. Copy Results: Save results for documentation

Documentation

  • Include Examples: Use parsed results in documentation
  • Share Safely: Only share test token examples
  • Update Regularly: Keep examples current
  • Version Control: Track changes to examples
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