Christian Mackie · London
Design Engineer at Shopify. Before that, years as a Shopify Solutions Architect and a Technical Product Owner at Gymshark.
These are my notes for everything and everyone. Find me as @mackiec everywhere, or at mackiec.xyz.
Notes
- Agentic Build RulesA set of general rules I abide by for all my agentic coding projects.
- Building Anti-Hallucination PatternsAdventures and lessons in trying to box agents into being reliable and trustworthy by design.
- Building Better Personal SoftwareTaking an AI-led coding practice from 'vibe code' to 'good software'.
- Building with Shopify's Dev MCP and Claude CodeLearn how to rapidly prototype and build Shopify discount functions and Admin UI Extensions using Claude Code and the Dev MCP
- Selected Samples Through Cart & CheckoutProviding sample selections in Cart, and then displaying them in Checkout
- Offering Gift Packaging via Checkout UI ExtensionBuilding a UI Extension that offers a simple custom Gift message and a material choice.
- [2025] Guide to Shopify CheckoutA comprehensive overview of Shopify's Checkout and how to extend it to suit your requirements.
- Alternative Checkout for Custom OrdersUsing Draft Order Invoice links as an alternative purchasing pathway to build totally unique checkouts.
- Adjust Prices via Checkout UI ExtensionModify a line item price based on additional selection options at Checkout.
- Conditional Delivery Instructions InputShow an optional delivery instructions field at Checkout based on a customer's address.
- Designing Solution WorkflowsBrainstorm a user journey or diagram to appropriately plan and build a solution to a problem.
- Informing Shopify Functions via UI External Network AccessUse a Checkout UI Extension to take input that generates an external request, and execute a Function on the response.
- Currency Adjusted Metafield with LiquidLearn how to handle currency conversion for a price metafield in Shopify using Liquid and Cart Transform Functions within a multi-currency store.