🔐 JWT Decoder Tool: Decode and analyze JSON Web Tokens (JWT) to view their header, payload, and signature components. This tool helps developers understand JWT structure, view claims, check expiration times, and learn about token anatomy.

📋 Example: Paste a JWT token like "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c" to see its decoded components.

🔍 JWT Decoder

📊 JWT Structure

HEADER Algorithm & Type

PAYLOAD Claims/Data

SIGNATURE Verification

📝 Paste your JWT token here:

📋 Header

📦 Payload

🔏 Signature

🔍 Claims Analysis

📚 Common JWT Claims Dictionary

iss Issuer - Who created the token

sub Subject - Who the token is about

aud Audience - Who can use the token

exp Expiration Time - When token expires

nbf Not Before - Token valid from this time

iat Issued At - When token was created

jti JWT ID - Unique identifier

❓ Frequently Asked Questions

🤔 What is a JWT token?

A JSON Web Token (JWT) 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.

🛡️ Is this tool secure?

Yes! This tool runs entirely in your browser. No JWT tokens are sent to any server. All decoding happens locally using JavaScript.

⚠️ Can I verify the signature?

This tool only decodes JWTs; it doesn't verify signatures. To verify a signature, you need the secret key or public key used to sign the token.

🔢 What are those timestamp numbers?

Timestamps in JWTs (like exp, iat, nbf) are Unix timestamps - the number of seconds since January 1, 1970. This tool converts them to human-readable dates.

🎨 What do the colors mean?

The visual diagram uses colors to distinguish JWT parts: blue for header (algorithm info), green for payload (your data), and orange for signature (verification).

📱 Can I use this on mobile?

Yes! This tool is fully responsive and works on all devices - phones, tablets, and desktops.

🚫 What if my token is invalid?

The tool will show an error if the token format is invalid. JWTs must have exactly three parts separated by dots, and the header/payload must be valid base64-encoded JSON.

📊 What are claims?

Claims are statements about an entity (typically the user) and additional metadata. There are registered claims (like exp, iss), public claims, and private claims.