COD Rules By Comeasy
Public Shopify app that controls Cash on Delivery with flexible, rule-based logic at checkout.
View on Shopify App Store
What we needed to solve.
- Merchants needed to hide or show Cash on Delivery based on country, region, postal code, products, customer tags, and cart value — without writing code.
- Checkout payment logic had to evaluate complex include/exclude combinations safely and fast within Shopify's strict execution limits.
- Admin UI had to feel Shopify-native so merchants could configure rules with zero learning curve.
How it was built.
Rust-powered Shopify Function
Built the payment-method validation as a Shopify Function in Rust so COD rules are evaluated server-side at checkout with sub-5ms performance and maximum reliability.
Remix + Polaris Admin UI
Used the Shopify Remix app framework with Polaris components and Web Components for a fast, Shopify-native admin experience.
Composable Rule Engine
Modelled rules as location, product/tag, customer-tag, and order-value conditions that combine into complex include/exclude logic for any checkout scenario.
The toolkit.
What's live.
The outcome.
Published as COD Rules By Comeasy with active merchant installs.
Evaluates rules server-side in under 5ms with zero downtime.
Merchants create complex checkout rules without developer assistance.
Maintains 99.99% uptime across global checkout transactions.
Merchants now control Cash on Delivery at checkout with flexible, rule-based logic — drastically reducing non-delivery RTO losses, powered by a high-speed Rust Shopify Function and Remix admin.
Core Shopify competencies.
- From-scratch full theme development
- Figma → Shopify (pixel-accurate)
- Liquid, HTML, CSS, JavaScript
- GraphQL Admin & Storefront API
- AJAX Cart & Storefront AJAX API
- Upsell & cross-sell integration
- App integration & configuration
- Marketing campaign pages
- Speed & Core Web Vitals optimization
- Accessibility (WCAG AA)
- Google Analytics 4 (GA4) setup
- WordPress / WooCommerce → Shopify
- Product, customer & order data import
- URL mapping & 301 redirects
- SEO parity & metadata migration
A clear path from brief to revenue.
Discovery
Understanding goals, audience, and constraints.
Strategy
Conversion plan, IA, and technical approach.
Design
Pixel-perfect interfaces aligned to brand.
Development
Clean, scalable Shopify implementation.
Optimization
Performance, SEO, A11y, and CRO.
Launch
QA, deploy, monitor, and iterate.
Verified Upwork reviews.
6 completed jobs · 5.0 average rating. Each project shipped with a perfect score from the client. View full profile on Upwork ↗
More case studies.
AI Product Recommendations for Global Brands
Works with global big brands — AI-powered discovery across GUESS, rag & bone, Beach Riot, Bombshell, and Miss Me.
GUESS Australia — AI Recommendations & Merchandising
AI-powered PDP rails, cart drawer cross-sells, and complete-the-look bundles for GUESS Australia.
rag & bone Australia — AI Search & Merchandising
AI-ranked search suggestions, related-product rails, and editorial merchandising for rag & bone.
Let's build your next Shopify success story.
Available for new Shopify Plus, theme, and custom app projects. Replies within 24 hours.