I have a website on shopify add API calls and a payment webhook -- 2

Hi there! I'm looking for an experienced web developer to help me with a project. I have a website built on shopify and I need to add API calls and a payment webhook. I'm not sure if I already have a webhook set up, so I'd like to have this be part of the project as well. I'm using a payment processor that is either Paypal, Stripe, or Square, so I'd like this part of the project handled as well. Thanks for your help!