Passing custom parameters with auth0.js authorize

Our application has an onboarding process where a new user has to first fill out a form which contains information like their first name, last name, gender, phone, address and some other fields etc after which they are redirected to the payment page.

Once a payment is successful we are redirecting them to the signup page. The signup page has the “Sign Up with Google” button and the custom email and password signup input fields. Once they signup > their account is created on Auth0 and they are logged into the web application.

We are using the auth0.js (auth0-js - npm) toolkit. The onboarding application is in next.js

Now, here’s the problem. The onboarding form which the user filled (containing name and other info) is saved into our MySQL db along with their payment success information. Once the user signs up with auth0 we need some way of connecting the auth0 user record with the personal info saved via the onboarding form.

The code looks something like this:

import auth0 from 'auth0-js';

const webAuth = new auth0.WebAuth({
  domain: process.env.NEXT_PUBLIC_AUTH0_DOMAIN || '',
  clientID: process.env.NEXT_PUBLIC_AUTH0_CLIENT_ID || '',

For sign up with Google we use

      connection: 'google-oauth2',
      responseType: 'code',
        `${process.env.NEXT_PUBLIC_LAUNCH_FRONT_END_URL}/login/callback` || '',
      scope: 'openid profile email',

and for custom user name and password

const onSubmit = (values: Inputs) => {
    try {
          connection: process.env.NEXT_PUBLIC_AUTH0_CONNECTION || '',
          password: values.password,
        function (err: any) {
          if (err) {
            if (typeof err?.description === 'string') {
            } else if (err?.code === 'invalid_password') {
              setError('password', {
                message: err?.policy,
            return err;
          } else {
            const url = webAuth.client.buildAuthorizeUrl({
              responseType: 'code',
                `${process.env.NEXT_PUBLIC_LAUNCH_FRONT_END_URL}/login/callback` ||
              scope: 'openid profile email',
    } catch (err) {

My plan is that when the user’s personal information is saved on mysql, I will return a guid which I would pass in to the auth0 authorize function. Upon auth0 user creation, I would like to save that guid on the user’s user_metadata, thus connecting them to their personal info record created on our mysql.

Is there a way to pass a custom parameter in both the cases of google sign in and custom signup flow which can be saved on user’s user_metadata?