JWT Decoder (Offline & Secure)
Free online JWT decoder — paste any JSON Web Token to decode header, payload, and signature. Auto-converts exp/iat timestamps to readable dates. 100% client-side.
How to use
- Paste a standard JWT string (starting with 'eyJ...') into the left input area.
- The token is automatically split into Header, Payload, and Signature sections.
- Timestamp claims like 'exp', 'iat', and 'nbf' are automatically converted to human-readable ISO dates.
- Click 'Copy' on any section to copy the decoded JSON to your clipboard.
Important Considerations
- Only standard 3-part JWTs (header.payload.signature) are supported.
- Encrypted JWTs (JWE) cannot be decoded without the encryption key.
- The signature is displayed raw — this tool does not verify signatures.
Privacy Notice: This tool is strictly client-side. All processing runs in your local browser memory using JavaScript. No text, tokens, payloads, or logs are ever transmitted to any remote server or analytics engine. You can even use this tool completely offline.
Keyboard Shortcuts
- Ctrl/Cmd + KOpen Command Palette to switch tools instantly.