JWT Tool

JWT Encoder & Decoder

Encode, decode, and verify JSON Web Tokens with support for multiple algorithms and full signature verification.

Paste your JWT token here

Analysis

Token Structure

Header

Payload

Signature

Signature Verification

Algorithm

Header (JSON)

Payload (JSON)

Algorithm

Secret (HMAC)

Understanding JWT

⚠️ Important: Decoding a JWT only reads its contents. It does NOT verify authenticity. Signature verification determines whether the token was signed by a trusted key.

A JWT consists of three Base64URL-encoded parts separated by dots:

Header: Contains metadata like algorithm (alg) and token type (typ)
Payload: Contains claims (statements about the entity and additional data)
Signature: Cryptographic signature to verify integrity and authenticity

Standard Claims:

iss - Issuer
sub - Subject
aud - Audience
exp - Expiration Time
iat - Issued At
nbf - Not Before
jti - JWT ID

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