In our region we have post machines, there are thousands of those. We would like to give a user a chance to choose from that list. In the background merchant will send the package to that post machine and client will get a SMS and can pick it up any time any day.
I could not find any way to do it normally. Only way I saw it would work is that this post machine choosing would happen outside of Shopify (as those lists are updated every 30 minutes, some machines might be unavailable etc). Another way I saw I could do it is with Carrier Service, by providing dynamically the list of post machines but it seems to be only for advanced plan. So if our app has hundreds of stores I don't think any of those are advanced plan.
What are more possibilities to control the shipping method view for client dynamically?
Could you tell me bit more what do you mean by: So if our app has hundreds of stores I don't think any of those are advanced plan? To use Carrier Service API your Shopify store needs to be on Advanced Plan (or higher). Thats all. Carrier Service API would be available on your Shopify store also if your Shopify plan is paid annually.