JWT Timestamp Helper

Convert between UNIX timestamps and human-readable dates for JWT expiration (exp) and issued at (iat) claims.

UNIX Timestamp

Date & Time

Understanding JWT Decoding

Why JWT Decoding Matters

JSON Web Tokens (JWT) are widely used for authentication and authorization in web applications. Being able to decode and inspect JWT tokens helps developers debug authentication issues, verify token contents, and understand the security claims being made.

How to Use This Tool

Paste your JWT token in the input field (or use the example button)
Click "Decode JWT" to parse the header and payload
Inspect the decoded JSON structures in the output panels
Use the timestamp helper to convert between UNIX timestamps and dates

Common JWT Examples

Standard JWT with User Claims

Contains user identity and basic claims:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE2MTYyMzkwMjJ9.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

JWT with Custom Claims

Includes application-specific permissions:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiJhYmNkMTIzIiwicm9sZXMiOlsiYWRtaW4iLCJ1c2VyIl0sInBlcm1pc3Npb25zIjpbInJlYWQiLCJ3cml0ZSJdLCJpc3MiOiJteS1hcHAiLCJpYXQiOjE1MTYyMzkwMjJ9.abc123def456ghi789

Frequently Asked Questions

Does this tool verify JWT signatures?

No, this tool only decodes the header and payload portions of the JWT. Signature verification requires the secret key and is not performed for security reasons.

Is my JWT token stored or transmitted anywhere?

No, all processing happens locally in your browser. No data is sent to any server or stored anywhere.

What happens if my JWT is malformed?

The tool will display clear error messages indicating whether the issue is with the JWT structure, Base64URL decoding, or JSON parsing.

Can this tool handle encrypted JWT (JWE)?

No, this tool only handles signed JWT (JWS) tokens. Encrypted JWTs require decryption keys and are not supported.

How It Works

Splits JWT into three parts: header, payload, and signature (using dot separator)

Decodes header and payload from Base64URL format

Parses decoded strings as JSON objects

Formats JSON with proper indentation for readability

Handles common JWT claims like exp, iat, nbf, iss, sub, aud

Converts UNIX timestamps to human-readable dates

Note: Base64URL decoding handles URL-safe Base64 variations and padding requirements automatically.

JWT Decoder

Header

Payload

Menu

JWT Decoder Header and Payload Viewer

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