JWTLens

JWT Decoder

Paste a JWT — see the decoded header, payload, and whether it's expired.

JWT structure

A JSON Web Token has three base64url-encoded parts separated by dots: header (algorithm and type), payload (claims like sub, iat, exp), and signature. The signature verifies the token hasn't been tampered with. JWTs are self-contained — the server doesn't need a database lookup to validate them.

Common JWT claims

Standard claims include: iss (issuer), sub (subject/user ID), aud (audience), exp (expiration timestamp), iat (issued at), nbf (not before), jti (unique token ID). Custom claims can hold any data. Never put sensitive information in a JWT payload — it's encoded, not encrypted.

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JWTLens

JWT Decoder

Paste a JWT — see the decoded header, payload, and whether it's expired.

JWT Token

Header

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}

Issued at: 2018-01-18T01:30:22.000Z
Expires at: N/A
Status: Valid

What you entered

Token parts: 3

1
Split token into 3 parts
header.payload.signature= eyJhbGciOiJIUzI1NiIs…
2
Decode header (base64url → JSON)
eyJhbGciOiJIUzI1NiIsInR5cCI6Ik= {"alg":"HS256","typ":"JWT"}
3
Decode payload (base64url → JSON)
eyJzdWIiOiIxMjM0NTY3ODkwIiwibm= 3 claims
4
Check expiration
No exp claim= No expiry

Result

Status: Valid

This JWT uses the HS256 algorithm. No expiration claim is present.

JWT Decoder

JWT structure

Common JWT claims

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