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JWT Builder

Build and sign JSON Web Tokens with custom claims and your choice of HMAC, RSA, or ECDSA algorithms. All signing happens in your browser.

Presets:

Algorithm

Secret

The secret is used to sign the token. Keep it safe — never share production secrets.

Standard Claims

Issuer (iss)Who issued this token

Subject (sub)Who the token is about

Audience (aud)Intended recipient

JWT ID (jti)Unique token identifier

Issued At (iat)Auto-set to current time

Not Before (nbf)Token valid from current time

Expiration (exp)Token expires after

No custom claims. Click "Add Claim" to add key-value pairs.

{
  "iat": 1773923383,
  "exp": 1773926983
}

HMAC (symmetric)

HS256 / HS384 / HS512

Shared secret key. Simple setup. Both signer and verifier need the same key.

RSA (asymmetric)

RS256 / RS384 / RS512

Public/private key pair. Private key signs, public key verifies. Most common in production.

ECDSA (asymmetric)

ES256 / ES384 / ES512

Elliptic curve keys. Smaller keys, same security as RSA. Faster verification.

Complement to JWT Decoder. Build tokens here, decode and inspect them there.

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