sign token is not equal with https://jwt.io/

Start with the inline crypto.generateKeyPairSync, jwt.sign, and jwt.verify reproduction; no repository file or test is named. Compare the two tokens and their decoded payloads, then trace the signing and verification inputs. The issue is resolved when the reported difference is explained and the expected behavior is covered by a reproducible test.

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmqThNdOtauJpQ8jmaSfM
gx4RCw/E1dX27/h25P3CSsVRVXITEiPKgyk7ZW/WNp97gc2wGch28FJTK+ULZk9D
G4Y2xzUcy666FwDkii8JAQa56jSppt3G9OPfp5iaYnynVpHHWyvNqTi9hfwtShsW
ObirZfjFVc25A+RwuBcOgHvNus6EEm13nldbL/dWqY+dWG0Us/jOoSZuAiaLAxwM
eJcwHM1rJj+6eUc8Bj41+U1Hdizn+U67BrolVnCtaWpnzGHyYDJlMakyJfoDqYEB
1bgWLcYuShvv//k2gdN+KMRueOfVFhbUiCG1eZy14FIvgJQt/0K4zYmfLF5YjUr4
SQIDAQAB
-----END PUBLIC KEY-----

-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----

const payload = { sub: 'user123', role: 'admin' };
const token = jwt.sign(payload, privateKey, { algorithm: 'RS256' });

eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyMTIzIiwicm9sZSI6ImFkbWluIiwiaWF0IjoxNjg4MTAxNzI4fQ.D3Pio6RmSnGsP3vhz50aJX8XPB5tRA4EdO8k2gTzpzh9gBms-8TJhTM0uez4THzUgT3PDjAYsQ0i-HGrRf74AcwMmm1Bc0zGwr3_MYNgx3fW7X12P-9ow9BzEF9bDH07cXulMqK2RDa-lvbD6ngGP926KKF9Jse9MIo3jGZ5377Ro0MpbB6bYktjDdo-y_U8oqsICdDO7YeVVshDwuxKboFGZAsbV1sYO1XU-15DfhkA0yF5i_lk6dhqsCco0KpIpmNQHAzWZCYSMZZ5DPd6kY9v7MCUDGfKcK_Gnx_KPo92_0k7IRMMNytZrhBsm0jasGIkE3XrLIsmo9588mvUbg

https://jwt.io/ token

eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyMTIzIiwicm9sZSI6ImFkbWluIiwiaWF0IjoxNjg4MTAxMzAwfQ.K7SToDIrmsAoXTny08R5HQPvkFTOZUVpudXzNuqk8L_JnBSVVlMys4cypK1CngUDiyZhrPwmqJEOcfOUlTEmWM1jorjgwz6KjleRcVzvEnSnzWOG2Gvh7LPm0taT8glSLtwXdSDYCMREwZgv2aVlberbZ8Br08SitxLp47askktIPlOz4IbvoixcUhrhCN2WpZGefcC5QaDQKjR2ca6ptjaAe3l-YRwCecqMSHqkeCHC2xQaoi2DXjS3ed5dDXF0sydql-Z9U9xv_2jO634jzEg4XFEVbKPmgvqZneCr6m5b44CQapxdv4RgIaHHtlunaqRCroKLV0zIx2UpK5Gd6Q

const crypto = require('crypto');
const jwt = require('jsonwebtoken');

const { privateKey, publicKey } = crypto.generateKeyPairSync('rsa', {
    modulusLength: 2048,
    privateKeyEncoding: {
        type: 'pkcs8',
        format: 'pem'
    },
    publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
    },
});


const payload = { sub: 'user123', role: 'admin' };
const token = jwt.sign(payload, privateKey, { algorithm: 'RS256' });
console.log("token=", token);

jwt.verify(token, publicKey, function (err, user) {
    console.log("=====")
    console.log(err)
    console.log(user) // user info from the token
    console.log("=====")
});