JWT Decoder
Decode and inspect JSON Web Token (JWT) Header, Payload, and expiration status in your browser without transmitting your token.
Header
{
"alg": "HS256",
"typ": "JWT"
}Payload Claims
Active{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022,
"exp": 1999999999
}100% In-Browser Privacy: This tool operates directly in your browser. None of your input text, documents, calculation values, or images are ever transmitted to or stored on our servers.
How to Use the JWT Decoder
Paste your encoded JSON Web Token (three dot-separated base64url segments) into the box.
Inspect the decoded Header (algorithm, token type) and Payload claims.
View parsed expiration timestamp (exp) and human-readable validity status (Valid vs Expired).
Worked Example & Demonstration
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9...
Payload: {"sub": "1234567890", "name": "John Doe", "admin": true}Technical Method & Underlying Formula
Base64url decoding of header and payload segments with Unix timestamp comparison against client clock.
Operational Boundaries: Note: This tool decodes claims for client inspection; cryptographic signature verification requires the server private/secret key.
Frequently Asked Questions
Is it safe to paste production JWTs here?
Yes. The token is decoded entirely in browser memory. It is never sent to our servers or stored anywhere.
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