New

JWT Generator

Runs in browser

Generate and sign JSON Web Tokens (JWT) with custom payload and secret. HS256 supported. Runs entirely in your browser.

JWT Generator tool

A JWT has three parts: header.payload.signature. With HS256, the signature is an HMAC over Base64URL(header) + "." + Base64URL(payload) using your secret. Everything runs locally in your browser.

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

Tip: Leave secret empty to preview header + payload encoding without a signature. For testing, set a secret and paste the output into JWT Decoder to verify the signature.

Generated JWT

Want to inspect a token? Open JWT Decoder.

How to use

  1. Start from a preset

    Pick a basic, auth, or complex preset to see realistic JWT payloads and common claims.

  2. Edit payload JSON

    Paste or modify the JWT payload. It must be a JSON object (not an array).

  3. Add time-based claims

    Optionally add `iat`, `nbf`, and `exp` as Unix timestamps to simulate real authentication tokens.

  4. Enter a secret

    Provide a secret to sign using HS256. Leaving it blank shows the unsigned `header.payload.` structure.

  5. Copy and verify

    Copy the generated JWT and open JWT Decoder to inspect header/payload and verify the signature with your secret.

Examples

  • Basic payload

    A minimal token with a subject and name.

    Input
    {
  "sub": "123",
  "name": "Alice"
}
    Output
    header.payload.signature

  • Auth token with expiry

    A realistic auth token with issuer, audience, roles, and expiration.

    Input
    {
  "iss": "https://api.example.com",
  "aud": "tooldock-web",
  "sub": "user_42",
  "email": "[email protected]",
  "roles": ["admin", "editor"],
  "scope": "tools:read tools:write",
  "iat": 1711324800,
  "exp": 1711328400
}

  • Complex nested payload

    Nested objects and arrays similar to production authorization data.

    Input
    {
  "iss": "auth.example.com",
  "aud": ["app-web", "app-mobile"],
  "sub": "user_123",
  "tenant": "acme",
  "features": {
    "beta": true,
    "flags": ["new-dashboard", "ai-tools"]
  },
  "device": {
    "id": "device_9f2c",
    "platform": "ios"
  },
  "permissions": [
    { "resource": "projects", "actions": ["read", "write"] },
    { "resource": "billing", "actions": ["read"] }
  ],
  "iat": 1711324800,
  "nbf": 1711324800,
  "exp": 1711332000
}

Frequently asked questions

Is my secret sent to a server?
No. Signing happens locally in your browser.
Which algorithm is supported?
HS256 (HMAC SHA-256) is supported for signing.
How do I verify the token?
Copy the generated JWT and open JWT Decoder. Paste the token, enter the same secret, and confirm the signature validates.
What format should exp/iat use?
Most JWT libraries expect `iat`, `nbf`, and `exp` as Unix timestamps (seconds since epoch).

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