JWT Decoder
Decode and inspect JWT headers, claims, and expiry dates privately.
Zero-Upload In-Browser Execution GuaranteeVerified Local RAM
Processed directly on your device. Nothing is uploaded. This tool uses native Web APIs, Canvas, and client-side WebAssembly to process your files inside local browser RAM. No server receives your file, no telemetry logs your data, and no account is required.
Key Capabilities
- Zero token leakage: token stays 100% inside your browser memory
- Decodes Header, Payload claims, and Signature segments
- Human-readable timestamps for 'exp' (expiration), 'nbf' (not before), and 'iat' (issued at)
- Live expiration countdown (Active vs Expired status)
How To Use
Paste Token
Paste your JWT string (e.g. eyJhbGci...).
Inspect Claims
View formatted Header and Payload JSON.
Check Expiration
Verify token validity and expiration status.
Frequently Asked Questions
Is it safe to paste real authentication tokens here?
Yes! There are no backend calls, analytics trackers, or logging endpoints. Decoding is purely Base64URL parsing in local browser JavaScript.
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