JSFiddle - React, Tailwind, and code Playground

JavaScript

const { Stripe } = require('stripe')
const stripe = new Stripe(process.env.STRIPE_TEST_SECRET_KEY, {
  apiVersion: '2020-08-27',
})

exports.handler = async (event) => {

    try {
        
        // get the stripe customer ID for this Knack account, and the return URL 
        const stripeCustomerId = event.queryStringParameters.stripe_customer_id;
        const returnUrl = event.queryStringParameters.return_url;
        
        // create a portal session
        const portalSession = await stripe.billingPortal.sessions.create({
            customer: stripeCustomerId,
            return_url: returnUrl,
        })
        
        // return the portal session to the frontend
        return {
            statusCode: 200,
            body: JSON.stringify({
              portalSession
            })
        };
    } catch (error) {
				// handle error
      }
};