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How JWTs Work and How to Decode Them

Understand JWT structure and the difference between decoding and verification.

A JWT has three parts

A JSON Web Token normally contains a header, payload, and signature separated by dots. The first two parts are encoded representations of JSON data.

Decoding is not verification

Anyone who has a JWT can decode its header and payload. That does not prove the token was issued by a trusted party or that its signature is valid.

Handle secrets carefully

Do not paste production credentials or sensitive tokens into a tool unless you understand exactly how the tool processes them. Client-side processing does not make an exposed credential safe to disclose.