Build a platform, embed the shopify API, enter the shopify domain name, and you can see the data

We have a shopify website, but we haven’t started to develop the shopify API, but we are considering developing it, and now we want to know, if we develop the shopify API, create a website, and add a certain number of shopify stores to the website, for example, we add 1000 Shopify store, how much does it cost (detailed costs, or documents)