Building a product monitor

Hi, I would like an app/ code which could alert me when certain products (preferably an interface where I can choose to add or remove products) come in stock. This monitor could alert me by sending discord notifications via a webhook. The products in question are shoes, which predominantly remain out of stock, and would need to be monitored for when they come in to stock, the sizing which comes in stock must be monitored. I require 4 such scripts, for 4 different sites. each script shall be able to scrape data of multiple products, I shall be able to add or remove from this list of products. furthermore, I would also like to monitor new additions to certain websites, on their home page or their new arrival or other sections. the discord alert should have the name, price, size in stock and the link to the product.