AI-TOL
👨‍💻 Dev

JWT Decoder - Decode and Verify JSON Web Tokens

Decode JWT tokens to view header, payload, and signature. Verify JSON Web Tokens and debug authentication. All processing happens locally.

Ready to try the tool?

It's free, fast, and privacy-focused. No registration required.

Try Jwt →

Introduction

JSON Web Tokens (JWT) are widely used for authentication and information exchange in web applications. Our JWT Decoder lets you inspect the contents of any JWT, view the header and payload, and verify the signature. Debug your tokens and understand what data they contain.

The tool runs entirely in your browser with no server-side processing. Your data never leaves your device, ensuring complete privacy and security. No registration required - just open and use.

Key Features

  • 1 Instant JWT decoding and display
  • 2 View header, payload, and signature separately
  • 3 Color-coded JSON syntax highlighting
  • 4 Validate JWT signature and structure
  • 5 Copy decoded JSON to clipboard
  • 6 Support for both compact and pretty JSON
  • 7 Error detection for malformed tokens
  • 8 Explanation of each JWT component
  • 9 Works with access tokens, ID tokens, and custom JWTs
  • 10 Privacy: all decoding in your browser
  • 11 No tokens stored or transmitted
  • 12 Mobile-friendly responsive design

How to Use

  1. 1 Paste your JWT token in the input field
  2. 2 View decoded header, payload, and signature instantly
  3. 3 Inspect claims in the payload: iss, exp, sub, etc.
  4. 4 Validate token signature and structure
  5. 5 Copy decoded JSON or individual claims to clipboard

Why Choose This Tool

⚡

Instant Decoding

Paste any JWT and see its contents immediately. No need to understand base64 encoding.

🔒

Color-Coded JSON

Decoded JSON is syntax-highlighted for readability. Easy to scan for specific claims.

🎯

Component Separation

Header, payload, and signature are shown separately. Understand each part's role clearly.

💎

Error Detection

Malformed tokens are flagged with helpful error messages. Debug authentication issues faster.

✨

Explanation Tooltips

Hover over any claim (exp, nbf, aud) to see what it means. Learn JWT as you debug.

🛡️

Complete Privacy

JWTs may contain sensitive user data. All decoding stays in your browser - tokens are never sent anywhere.

Common Use Cases

1
Use Case

Debug authentication issues in web applications

2
Use Case

Inspect access tokens and ID tokens from OAuth providers

3
Use Case

Verify token claims before accepting them in your code

4
Use Case

Understand what data your JWT contains

5
Use Case

Test token expiration and renewal logic

6
Use Case

Decode API tokens for debugging requests

7
Use Case

Learn JWT structure and standard claims

8
Use Case

Validate token signature for security testing

Frequently Asked Questions

Is it safe to decode JWT tokens here? ▼
Yes! JWT decoding happens entirely in your browser. Your tokens are never sent to any server. JWT tokens contain encoded information that's meant to be read - decoding them is safe and necessary for debugging. However, never share secret keys used to sign tokens.
What information can I see in a JWT? ▼
Decoding a JWT reveals the header (algorithm and token type), payload (claims like user ID, expiration, issuer), and signature verification status. This helps debug authentication issues without needing backend access.
Can I create or sign JWT tokens? ▼
This tool is for decoding and viewing JWT tokens. It doesn't create or sign tokens, as that would require handling secret keys which should never be done in a browser environment for security reasons.

Start Using Jwt Now

It's completely free, privacy-focused, and requires no registration.

Try Jwt →

Explore More Tools

📚

All Documentation

Browse help articles for all tools

🔑

Try JWT Decoder

Open JWT Decoder

🔐

Base64 Tool

Encode and decode Base64