The Customer Portal Session URL API allows you to create a link for a customer where they can add their Payment Methods. The link will take them to your processor-hosted Customer Portal. 

The Customer Portal layout and configuration can only be set up in the payment processor. Check their official guide: 

When creating a Customer Portal URL, use the reqObj in the request to pass in the Customer and Payment Processor data. The returned response is in a JSON format that contains the URL to be shared with the customer.

Currently, the Customer Portal Session URL is supported by 

Create

Customer Portal Session URL

Stripe

Breadwinner Payments Docs

App Installation

Connect to Stripe

Connect to Braintree

Connect to Square

Connect to Payment Processor

Customer Match

Update Page Layouts

Getting Started

Create Customer

Create Transaction

Create Subscription - Stripe

Create Subscription - Square

Create Subscription

Create Invoice - Stripe

Create Invoice - Square

Create Invoice

Guided Wizard

Transaction

Invoice

Button URL Structure

Button URL Generator

Custom Guided Wizard

Braintree

Square

Auto-match Payment Transactions with Customers

Custom Fields

Additional Configuration

API Overview

Customer

Subscription

Checkout URL

Request

Response

Global API

Requirements

ERD / Object Structure

ID Locations

Technical Resources

Getting Help