We sell men suits, and on Shopify, clients can only choose the size such as 40 Regular. On our internal website (not on Shopify), we have a lot of customizations such as button selection and color and many others.
We would like to update the Shopify product page where we display these options to our clients, via probably an iFrame (unless there's a different way to do it), clients can interact with this "app" on the product page (this would be running from our own website), and we will process these customizations on our internal website.
Once the client is ready to complete the purchase, we would then send these customization and their prices to Shopify, so that the Shopify cart will display the initial product (the suit) as well as a list of the customizations the client did, such as button selection, button color... and they can then checkout on Shopify.
How can we achieve this? mainly:
Load a web app we built into the product page (probably using an iFrame?)
Client interact with our app, choosing options like custom buttons and colors.
Our app will receive product info from Shopify.
Our app will send back to Shopify the added options and their additional prices.
Client will checkout on Shopify and they will see the product options and additional price upgrades on their cart.