JWT Token Analyzer

Debug and audit JSON Web Tokens locally. Perfect for security testing and API development.

Encoded Token
HEADER: ALGORITHM & TOKEN TYPE
// Paste a token to see details
PAYLOAD: DATA
// Data claims will appear here
SIGNATURE VERIFICATION
// Signature structure and hash info

The Architecture of JSON Web Tokens (JWT)

A JSON Web Token is a compact, URL-safe means of representing claims to be transferred between two parties. It consists of three parts separated by dots: Header, Payload, and Signature. Header typically specifies the signing algorithm; Payload contains the user data (claims), and Signature ensures the token hasn't been tampered with.

Why Audit Locally?

Many online JWT debuggers send your tokens to their servers for parsing. This is a severe security risk, as JWTs often contain sensitive identity information and session tokens. Our JWT Analyzer performs all decoding 100% locally in your browser's RAM, ensuring your authentication tokens never leave your machine.

Auditing Expiration and Claims

The "exp" (Expiration) claim is one of the most critical parts of a JWT. Our tool automatically detects this claim and calculates whether the token is still valid or has expired. This helps developers debug "401 Unauthorized" errors quickly by identifying if a login session has timed out without requiring complex server logs.

Trust but Verify

While this tool decodes the data for inspection, remember that any data seen in a JWT should only be trusted if the Signature has been verified using a secure secret or public key on your backend system.

? How to Use JWT Token Analyzer

  1. Open the tool directly in your browser — fully private.
  2. Enter your data, password, or text into the input field.
  3. Select the desired security algorithm or strength settings.
  4. Click the action button to generate or analyze the result.
  5. Copy or download your output. All processing stays on your device.

✓ Why Use This Tool

  • 100% Free — No account, subscription, or payment required.
  • Privacy First — All processing happens in your browser. Your files never leave your device.
  • No Installation — Works directly in any modern browser on any device.
  • Instant Results — Get your output in seconds without waiting for server processing.

Frequently Asked Questions

Are the passwords generated by this tool stored anywhere?

No. Password generation uses your browser's built-in cryptographically secure random number generator (window.crypto). Nothing is stored, logged, or transmitted.

How strong is a randomly generated 16-character password?

A 16-character password using uppercase, lowercase, numbers, and symbols has approximately 95^16 possible combinations — far beyond practical brute-force capability with current computing hardware.

Can I use these security tools for professional or enterprise work?

Yes. All tools are built on standard cryptographic specifications. The hash tools use SHA-256 and MD5 per their official specifications, making them suitable for verification and professional use.