Why are my rates duplicated on the Store Checkout but the App Sandbox works correctly?
If you're seeing your rates getting duplicated on your store checkout, although on the App Sandbox the tests work correctly, there are two main reasons for this; Multi-Location and Shopify Profiles.
If you have different locations or warehouses from where you fulfill from, where the inventory is managed.
Basically, if a cart contains products whose inventory is coming from different locations (if the stock is being fulfilled from multiple locations), Shopify will send 3rd-party carrier apps, like Postcode Shipping, separate requests and blend the rates together.
The only solution we have seen is having a single source of inventory. Sadly we depend on Shopify willingness to make changes to multi-location for carriers (at least with their current approach to 3rd-party carrier rates).
If you've configured different Shopify profiles in your shop, assigning rates to each one of the groups.
Similar to Multi-Location, if the products in the cart are in different shipping profiles, it's expected to get duplicated rates. Unfortunately, Shopify does not send profiles to carrier apps; the app will get a different request from each profile. Therefore, if a customer orders multiple items from your store and they come from different profiles, Shopify will query for shipping rates multiple times and add them together.
Essentially, Shopify will send different requests to the app, and they get quoted on their own. Then when the customer checks out the rates are combined if their titles match. That is why they may see the price double. The only way to stop it is to have the products in the same profile in your Shopify Admin.
If you're not doing anything advanced with your Shipping Profiles (e.g. different sending locations or inventory stocking), you may consider deleting your Shipping Profiles and have the Product Groups configured in our app.
NOTE: If Shopify sends those different requests (Fulfilled from different locations or the items belong to two different profiles) and we send back two rates with different titles, Shopify blend the rates together by summing the rate prices and changing the titles to "Shipping". They'll use the rate titles only if they are blending two rates with the exact same title.
Visit the Shopify article about Combining shipping rates from different shipping profiles at checkout
If you're using a subscription app, and notice inconsistency with your rates at checkout when items in the cart contain products for recurrent purchase, then it's likely caused by the Subscription app. Subscription apps don’t integrate seamlessly with the Shopify Carrier endpoints to source rates from carrier apps that you might have installed, like Postcode Shipping. To resolve this, you may want to contact the subscription app you’re using and ask them how to integrate their app with third-party carrier apps. Postcode Shipping doesn't do anything out of the ordinary in our integration with Shopify, so if they have a solution for integrating with carrier apps, then it should work for Postcode Shipping too.
Multi-Location
If you have different locations or warehouses from where you fulfill from, where the inventory is managed.
Basically, if a cart contains products whose inventory is coming from different locations (if the stock is being fulfilled from multiple locations), Shopify will send 3rd-party carrier apps, like Postcode Shipping, separate requests and blend the rates together.
The only solution we have seen is having a single source of inventory. Sadly we depend on Shopify willingness to make changes to multi-location for carriers (at least with their current approach to 3rd-party carrier rates).
Shopify profiles
If you've configured different Shopify profiles in your shop, assigning rates to each one of the groups.
Similar to Multi-Location, if the products in the cart are in different shipping profiles, it's expected to get duplicated rates. Unfortunately, Shopify does not send profiles to carrier apps; the app will get a different request from each profile. Therefore, if a customer orders multiple items from your store and they come from different profiles, Shopify will query for shipping rates multiple times and add them together.
Essentially, Shopify will send different requests to the app, and they get quoted on their own. Then when the customer checks out the rates are combined if their titles match. That is why they may see the price double. The only way to stop it is to have the products in the same profile in your Shopify Admin.
If you're not doing anything advanced with your Shipping Profiles (e.g. different sending locations or inventory stocking), you may consider deleting your Shipping Profiles and have the Product Groups configured in our app.
NOTE: If Shopify sends those different requests (Fulfilled from different locations or the items belong to two different profiles) and we send back two rates with different titles, Shopify blend the rates together by summing the rate prices and changing the titles to "Shipping". They'll use the rate titles only if they are blending two rates with the exact same title.
Visit the Shopify article about Combining shipping rates from different shipping profiles at checkout
Subscription apps
If you're using a subscription app, and notice inconsistency with your rates at checkout when items in the cart contain products for recurrent purchase, then it's likely caused by the Subscription app. Subscription apps don’t integrate seamlessly with the Shopify Carrier endpoints to source rates from carrier apps that you might have installed, like Postcode Shipping. To resolve this, you may want to contact the subscription app you’re using and ask them how to integrate their app with third-party carrier apps. Postcode Shipping doesn't do anything out of the ordinary in our integration with Shopify, so if they have a solution for integrating with carrier apps, then it should work for Postcode Shipping too.
Updated on: 06/09/2023
Thank you!