Text-Tools

JWT Decoder

Decode JSON Web Tokens.

100% Private - Your text never leaves your browser
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About JWT Decoder

Decode and inspect JWT tokens to view header, payload, and signature. Debug authentication issues easily. This free online tool processes your text instantly in your browser - no data is ever sent to any server, ensuring complete privacy.

How to Use JWT Decoder

  1. Paste or type your text in the input field on the left
  2. The result appears automatically in the output field
  3. Adjust any options below the text fields if available
  4. Click "Copy Result" to copy the output to your clipboard
  5. Use "Download" to save the result as a text file

Features

  • ✓100% Free - No registration required
  • ✓Instant processing as you type
  • ✓Complete privacy - works offline
  • ✓No file size limits
  • ✓Works on all devices
  • ✓Download results as text file

Why Use Our JWT Decoder?

Unlike other online tools that require uploads or send your data to servers, our jwt decoder runs entirely in your browser using JavaScript. This means your sensitive text never leaves your computer, making it perfect for processing confidential documents, personal information, or any text you want to keep private. The tool is also lightning-fast since there's no network latency involved.

When to Use This Tool

Debug Authentication

Inspect JWT claims to debug login issues, permission errors, or token expiration problems.

Verify Token Contents

Check that JWT payload contains expected user info, roles, and permissions.

Check Expiration

Decode tokens to see exp (expiration) and iat (issued at) timestamps.

API Development

Verify JWT structure during API development and integration testing.

Examples

Decode Header

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
{"alg": "HS256", "typ": "JWT"}

💡 Header shows algorithm and token type

Decode Payload

...eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4ifQ...
{"sub": "1234567890", "name": "John", "exp": 1609459200}

💡 Payload contains claims like user ID and expiration

Common Mistakes to Avoid

⚠️

Thinking decoding = verifying

Solution: Anyone can decode a JWT! Decoding doesn't verify the signature. Only the server with the secret can verify.

⚠️

Storing sensitive data in JWT

Solution: JWTs are only Base64 encoded, not encrypted. Never put passwords or secrets in JWT payload.

⚠️

Ignoring token expiration

Solution: Check "exp" claim. Unix timestamp like 1609459200 means it expired on that date. Compare with current time.

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