ℹ️ About this tool
Free Online JWT Decoder & Debugger
QuickTools JWT Decoder lets you instantly decode, inspect and debug JSON Web Tokens. Paste any JWT and see its header, payload and signature clearly separated and syntax-highlighted. The tool automatically analyzes claims like exp, iat, sub and iss with human-readable labels and live expiration countdown. Use the Payload Editor to modify claims for testing purposes (without re-signing). Everything runs 100% client-side — your tokens never leave your browser. Perfect for developers debugging authentication flows, API integrations or OAuth implementations.
How to Decode a JWT
Paste your JWT token into the input field. The decoder automatically splits it into Header, Payload and Signature sections with syntax highlighting. Claims are analyzed with human-readable labels and a live expiration countdown.
Why Use This Tool
100% client-side — your tokens never leave your browser. Live expiration countdown, color-coded sections, claim analysis, and a unique Payload Editor for testing modified tokens.
FAQ
Is my JWT token safe?
Yes. All processing happens in your browser. Your token is never sent to any server.
Can this tool verify JWT signatures?
This tool decodes and inspects tokens. Signature verification requires the secret key which is never shared client-side.
What is the Payload Editor?
It lets you modify the payload JSON and generate a new token for testing purposes. The signature won't match — it's for debugging only.
Does it support all JWT algorithms?
Yes, the decoder works with any JWT regardless of the signing algorithm (HS256, RS256, ES256, etc.).
What claims are automatically analyzed?
exp (expiration with live countdown), iat (issued at), sub (subject), iss (issuer), aud (audience), and more.
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