Creating a new Shopify app and a new Woocommerce plugin

Our goal is to integrate our existing loyalty program with Shopify and Woocommerce. In order to do that, we need to develop our own plugins. We already have APIs that can be utilized by these newly created plugins. Here is what these plugins need to do: At the installation time: 1- At the installation time, ask for API URL, User name and password and authenticate the user against our existing system 2- Generate and store a token on Woocommerce/Shopify. Also post the generated token to our API. This token will be used to identify the client going forward. 3-Add 2 fields to payment page of the Woocommerce/Shopify for users to be able to enter their loyalty number and their password (pin) For customers: 1- At the checkout, consumers enter their loyalty number and password and authenticate against our existing system 2- An API will be called to get the available points for the customer 3- Customers have the option to redeem their balance if they wish 4- Redeemed option will be deducted from the total amount 5- Their new balance as well as their their redeemed amount will be send to our existing system (using our APIs) More details can be shared with freelancers who have experience building plugins and integrating external apps with Woocommerce and Shopify.