Editing Shopify checkout

Shopify Apps

Topic summary

A new Shopify app developer is building an integration with InPost, a Polish automated locker delivery service. The goal is to let customers select a “paczkomat” (locker) during checkout, with the selection visible in both cart and checkout.

Key Challenge:
Checkout extensions require Shopify Plus, but the developer wants a free solution accessible to all merchants.

Proposed Solution:

  • Use the cart page instead of checkout for paczkomat selection
  • Implement a custom widget/dropdown that loads available lockers via InPost’s API
  • Store selection using cart attributes or order notes, which merchants can view in order details

Implementation Steps:

  1. Enable order notes in the Shopify theme
  2. Add a paczkomat selector to the cart page with dynamic options
  3. Pass selected data through cart attributes
  4. Test to ensure data appears in merchant order details

Alternative: Build a public app using Shopify’s Admin or Storefront API with an installable widget for broader merchant use.

Status: Discussion remains open for further questions.

Summarized with AI on November 2. AI used: claude-sonnet-4-5-20250929.
1

I am a new Shopy app developer and have been learning for the past 10 days. I am working on creating an app that integrates with In Post, a service allowing customers to choose delivery to automated lockers called “paczkomaty” in Poland.

My goal is to allow customers to select a paczkomat during checkout, and I would like this selection to be visible in the cart and carry over to checkout. Can you help me understand if this is possible and how to implement it?
I know there is something like checkout extension but its only works for shopify plus members - but i want create something free for everyone

2

Hi @znicz1

Yes, it’s possible to integrate InPost’s paczkomaty selection into your Shopify store without requiring Shopify Plus or its checkout extensions. Here’s how you can approach it:

1. Understand the Shopify Checkout Limitations

Shopify limits customizations to the checkout process for stores on non-Plus plans. However, you can use workarounds by leveraging Shopify’s cart page and order notes to capture user input before checkout.

2. Approach to Implement Paczkomaty Selection

Since you’re working with a free-for-all app, you’ll need to:

  1. Add a Paczkomaty Selection to the Cart Page
    Use a custom widget, dropdown, or modal on the cart page where customers can select their desired paczkomat. You can load InPost’s API data (list of available lockers) here.
  2. Store the Paczkomat Data in Order Notes
    Shopify allows storing additional data using cart attributes or order notes. You can pass the selected paczkomat data through order notes, which merchants can see on the order details page.

3. Implementation Steps

Here’s a simplified breakdown:

Step 1: Enable Order Notes on the Shopify Theme

  1. Go to your Shopify admin > Online Store > Themes > Customize.
  2. Select the Cart page and enable Order Notes.

This allows a field where additional data can be added.

Step 2: Add a Paczkomaty Selector You’ll need to modify your cart page to include a paczkomaty selector. Here’s a basic example:

Select your Paczkomat:

This dynamically populates lockers using InPost’s API.

Step 3: Display Paczkomat Data in the Order Notes The selected paczkomat will be stored under attributes[paczkomat] and sent with the order. Merchants can view this data under the “Additional Information” section in the order details.

Step 4: Testing

  1. Test the cart functionality to ensure the paczkomat selection is saved.
  2. Verify that the selected data appears in the order details for merchants.

4. Alternative Option: Build a Public App

If you’re building an app to integrate InPost paczkomaty for broader use:

  • Use Shopify’s Admin API or Storefront API to manage the cart and send paczkomaty data.
  • Provide a script or widget that merchants can easily install.
  • Make it configurable so they can input their InPost API credentials.

Final Thoughts

It’s doable even without Shopify Plus! The cart page and order notes are flexible enough to implement this feature for any plan. If you want a cleaner implementation, you could eventually explore building a Shopify App with embedded widgets.

If you need any other assistance, feel free to reply and I will try my best to respond.
Best regards,
Daisy