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JWT Generator & Signer

Create and sign JSON Web Tokens with HS256, HS384 or HS512 algorithms. Set custom claims and expiry. Runs entirely in your browser.

🔒 Security Tools Free Browser-based

Tool

Algorithm

Expiry

Secret Key

Payload (JSON)

JWT Token

Secret Key (for HMAC verification)

What is a JWT?

A JSON Web Token (JWT) is a compact, URL-safe token for transmitting claims between parties. It consists of three Base64url-encoded parts separated by dots: Header (algorithm), Payload (claims) and Signature (integrity proof).

Standard JWT Claims

Claim	Name	Description
`sub`	Subject	Identifies the principal (e.g. user ID)
`iss`	Issuer	Who issued the token
`aud`	Audience	Intended recipients
`exp`	Expiration	Unix timestamp when the token expires
`iat`	Issued At	Unix timestamp when the token was issued
`jti`	JWT ID	Unique identifier for the token

HMAC vs RSA Signing

HS256/HS384/HS512 use a shared secret — both parties must know the same key. RS256/ES256 use asymmetric keys — the signer uses a private key and verifiers use the corresponding public key. Use HMAC for server-to-server tokens and RSA/EC for tokens verified by third parties.