Is this JWT Decoder secure?

Yes — decoding happens entirely in your browser. No token data is uploaded or stored on any server.

Can you decode the signature?

No. The signature is not decodable data — it’s a cryptographic value used to verify that the header and payload haven’t been tampered with.

Does decoding validate the token?

Decoding only parses the token. This tool can check time-based claims like exp and nbf, and can optionally verify HS256 signatures when you provide a secret key.

JWT Decoder

Decode JWT header and payload, validate time-based claims (exp, nbf), and inspect standard claims — all locally in your browser. No data is sent to any server.

Privacy: All decoding happens locally in your browser. No data is sent to any server.

Paste a JWT to decode

JWT token0 chars · 0 bytes

Issuer (iss)

—

Audience (aud)

—

Expiration (exp)

—

exp (local time)

—

Issued at (iat)

—

Not before (nbf)

—

Do not share sensitive tokens publicly. Anyone can decode JWT contents; treat them like secrets.

Header

Header JSON will appear here

Payload

Payload JSON will appear here

SignatureWhat is this?

Signature will appear here

The signature proves the token wasn’t modified. You can’t “decode” it — you can only verify it using the right key.

HS256 verification (optional)Provide a secret to verify HS256.

All decoding happens locally in your browser. No data is sent to any server.

How to Use This Tool

Paste your JWT into the input box.
Review decoded Header and Payload side by side.
Check validity status (expired / not active yet / valid) based on exp and nbf.
Optionally verify HS256 signatures by providing the shared secret.
Copy or download the decoded JSON.

Frequently Asked Questions

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