Free JWT Decoder Online
Decode and inspect JSON Web Tokens (JWT) instantly. View header, payload, and verify token contents with our free online JWT decoder.
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. JWTs are commonly used for:
- Authentication
- Authorization
- Information exchange
- Single Sign-On (SSO)
JWT Structure
A JWT consists of three parts separated by dots:
header.payload.signature
Header
Contains token type and signing algorithm:
{
"alg": "HS256",
"typ": "JWT"
}
Payload
Contains claims (user data and metadata):
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022
}
Signature
Verifies the token hasn't been tampered with.
How to Use
- Paste your JWT token in the input field
- Click "Decode JWT"
- View the decoded header and payload
- Check token status (expired/valid)
Features
- Header decoding - View algorithm and type
- Payload inspection - See all claims
- Timestamp parsing - Human-readable dates
- Expiration check - Know if token is expired
- Copy sections - Copy header, payload, or signature
Common JWT Claims
| Claim | Description |
|---|---|
iss | Issuer |
sub | Subject (user ID) |
aud | Audience |
exp | Expiration time |
iat | Issued at |
nbf | Not before |
Security Notes
- Never share tokens containing sensitive data
- Tokens are not encrypted - anyone can decode them
- Signature verification requires the secret key
- Check expiration before trusting a token
Why Use Our Tool?
- Instant decoding - No setup required
- Privacy first - All processing in your browser
- Detailed view - See all token components
- Timestamp conversion - Human-readable dates
- Sample token - Learn with examples
Decode JWTs quickly and safely!