Send list of products in liquid response in app proxy

[srin_6degree]

Hello all,

I am new to Shopify apps and app proxy.

We were building an app to streamline Exchange of items in an order.

From the inputs from the community we were able to understand and are implementing the same.

I wanted to know how to list set of products as part of response in app proxy. We want to send liquid code as 

response. However not clear on how to send this list of products/variants so that when the liquid code is executed 

in the store portal, the products are displayed to the customer.

Can anyone please give some directions or suggestions?

Thanks in advance,

Srinivasa Pradeep