JWT Decoder
Decode and inspect JSON Web Tokens (JWT) safely on your local device. View header parameters, payload claims, and expiration timestamps without transmitting sensitive authentication tokens over the network.
{
"alg": "HS256",
"typ": "JWT"
}{
"sub": "user_123456",
"name": "Alex Mercer",
"role": "admin",
"iat": 1516239022,
"exp": 2524608000
}7f23x9kL42xQZp8kM41x7Q_aB2C3D4E5F6G7H8I9J0K
100% Client-side token inspection
Unlike cloud-hosted JWT debuggers that send secret bearer tokens and claims over remote internet connections, FileKinetix decodes and validates tokens entirely inside browser memory. Your secrets, session IDs, and user claims stay strictly confidential on your machine.
Automated claim parsing and countdown
The tool automatically detects and formats standard JWT claims (such as expiration time 'exp', issued-at 'iat', issuer 'iss', and subject 'sub'), instantly showing whether your token is active or expired.
How to decode JSON Web Tokens
- Paste your encoded JSON Web Token (JWT) into the text area.
- View the formatted Header and Payload JSON structures.
- Check the active/expired token status and expiration countdown.
- Click 'Copy Payload' or 'Copy Header' to copy formatted JSON to clipboard.
Frequently Asked Questions
Is my JWT token transmitted or stored on any server?
No. The decoding runs 100% locally in your web browser. No token data is ever logged, sent, or saved remotely.
Does this tool verify cryptographic token signatures?
This tool decodes and parses the structure of the JWT (Header, Payload, Claims). To verify cryptographic signatures, you would need the matching public key or secret.