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JWT Decoder

LiveDeveloper Utilities

JWT Decoder is a free, privacy-first tool for developers working with authentication and authorization. Paste any JSON Web Token to instantly decode and inspect the header and payload. The tool shows color-coded token segments, explains standard claims (iss, sub, aud, exp, iat, nbf, jti), displays live expiry countdown, and highlights security details like the signing algorithm. Everything runs client-side — your tokens never leave your browser.

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Output Summary

Export and sharing workflow optimized for web content formats.

Key Features

Instant JWT decoding with color-coded token segments
Header and payload displayed as formatted JSON
Live expiry status: valid, expired, or no expiry set
Countdown timer showing exact time remaining until expiry
Standard claim explanations (iss, sub, aud, exp, iat, nbf, jti)
Signature algorithm and token type detection
Copy header, payload, or full decoded output individually
Load sample JWT to explore the tool instantly
100% client-side — tokens never leave your browser
Dark mode and light mode with responsive layout

FAQs

What does the JWT Decoder do?

It takes a JSON Web Token (JWT) string and decodes it into its three parts: the header (algorithm and type), the payload (claims and data), and the signature. It also shows whether the token is expired and explains what each standard claim means.

Is it safe to paste my JWT token here?

Yes. The JWT Decoder runs 100% in your browser. No token data is ever sent to a server, stored, or logged. Your sensitive authentication tokens stay completely on your device.

Can this tool verify JWT signatures?

This tool decodes and inspects JWTs but does not verify signatures, as that requires the secret key or public key. It is designed for debugging and inspection, not cryptographic verification.

What JWT claims are explained?

The tool explains all standard registered claims: iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID). Custom claims are displayed as-is.

Does it work with all JWT algorithms?

Yes. The decoder works with any JWT regardless of signing algorithm (HS256, RS256, ES256, PS256, etc.) since it only decodes the base64url-encoded header and payload without needing the signing key.

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