How to add Handling Fee at Checkout using custom app.

Shopify Apps

Topic summary

A developer seeks guidance on implementing an additional handling fee at checkout through a custom Shopify app.

Key Questions:

  • Whether Shopify Functions or APIs can programmatically apply handling fees during checkout, and how to define/configure such functions
  • Which APIs or approaches work best when using App Extensions for this purpose
  • What specific permissions or prerequisites are needed to modify the checkout flow

Current Status:
The discussion remains open with no responses yet. The developer has requested examples, best practices, and relevant documentation to guide implementation.

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

How to implement an additional handling fee at checkout through a Custom-developed app. Functions or App Extensions can be used for this, but I need guidance on the following:

  1. Can Functions or APIs be used to apply a handling fee programmatically during the checkout process? If so, how should I define and configure the function?
  2. If using App Extensions, what APIs or approaches should I use to achieve this?
  3. Are there specific permissions or prerequisites required to modify the checkout flow in this way?

Any examples, best practices, or relevant documentation links would be greatly appreciated. Thank you!

1 Like