Encoding & Utility Tools
JWT Decoder & Inspector
Decode any JSON Web Token (JWT) into its header, payload, and signature segments. All claims are explained in plain English, expiry status is shown live, and algorithm security is flagged. No signature verification — this tool only decodes the Base64-encoded segments. Never share or paste production secrets here.
All processing happens locally in your browser. No data is uploaded.
JWT Token
Segments
📋 Header
📦 Payload
🔐 Signature
▶ Raw JSON (header + payload)
Standard JWT Claims Reference
| Claim | Full Name | Description |
|---|---|---|
| iss | Issuer | Who issued the token (e.g. auth server URL) |
| sub | Subject | Who the token is about (usually user ID) |
| aud | Audience | Who the token is intended for |
| exp | Expiration | Unix timestamp when token expires |
| nbf | Not Before | Token not valid before this time |
| iat | Issued At | When the token was issued |
| jti | JWT ID | Unique identifier to prevent replay attacks |