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JWT Decoder & Inspector - JSON Web Token Tools

Decode JSON Web Tokens instantly to inspect headers, payload claims, and verify expiration. Analyze your JWT authentication tokens with our secure browser-based decoder.

Enter JWT Token

What are JSON Web Tokens?

JSON Web Tokens (JWT) are an open industry standard (RFC 7519) for representing claims securely between two parties. They provide a compact, URL-safe way to transmit information that can be verified and trusted through digital signatures.

Our JWT decoder allows you to inspect any JWT token's structure, validate its format, check expiration status, and understand the claims contained within the payload—all processed securely in your browser.

Key Features

  • Complete JWT inspection: Decode header, payload, and signature sections
  • Expiration validation: Automatically checks if tokens are expired
  • Tabbed interface: Easy navigation between JWT components
  • Copy functionality: One-click copying of decoded sections
  • Error handling: Clear feedback for invalid JWT format
  • Privacy focused: All processing happens locally in your browser

Common Use Cases

Authentication

Decode tokens from login systems to verify user identity and access permissions.

API Debugging

Inspect JWT tokens in API requests and responses to troubleshoot authentication issues.

Token Analysis

Examine token structure, claims, and metadata for security auditing and compliance.

Development Testing

Verify token generation and validate claims during application development and testing.

How to Use the JWT Decoder

Step-by-Step Instructions

  1. Paste your JWT token into the input field
  2. The tool automatically validates and decodes the token
  3. Click tabs to view Header, Payload, or Signature sections
  4. Check expiration status in the Payload tab
  5. Copy decoded sections using the Copy buttons
  6. Review any error messages for invalid tokens

Understanding JWT Structure

  • Header: Contains token type (JWT) and signing algorithm
  • Payload: Contains claims and user data
  • Signature: Verifies authenticity and integrity

Pro Tips

  • JWT tokens contain three Base64URL-encoded parts separated by dots
  • The tool shows expiration status with color coding (green/red)
  • All decoding happens locally - tokens never leave your browser
  • Invalid tokens will display helpful error messages
  • Common claims include sub (subject), iat (issued at), exp (expiration)
  • The signature section cannot be decoded but can be verified with the secret

JWT Token Components Explained

Header

Typically contains the token type ("JWT") and the signing algorithm being used (e.g., "HS256", "RS256").

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

Payload

Contains the claims - statements about the entity (user) and additional data. Can include standard and custom claims.

{"sub":"user123","exp":1735689600}

Signature

Created by encoding the header and payload with a secret key. Used to verify the token hasn't been tampered with.

SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

Why Use Our JWT Decoder?

Our JWT decoder provides a comprehensive view of your tokens with advanced features like expiration checking, error validation, and organized tabbed display. Unlike basic decoders, we offer detailed explanations and handle edge cases gracefully.

Security is paramount - all token processing happens entirely in your browser, ensuring your sensitive JWT data never leaves your device. Perfect for developers, security professionals, and anyone working with JWT-based authentication systems.