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Public Shopify App

COD Rules By Comeasy

Public Shopify app that controls Cash on Delivery with flexible, rule-based logic at checkout.

View on Shopify App Store
COD Rules By Comeasy — Comeasy — Shopify App Store
Client
Comeasy — Shopify App Store
Industry
Shopify Apps · Checkout Tooling
Role
Full-stack Shopify App Developer
Duration
12 weeks
Public
App Store listing
Rust
Shopify Function
24/7
Merchant support
No-code
Setup
The Challenge

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.
  • Admin UI had to feel Shopify-native so merchants could configure rules with zero learning curve.
The Approach

How it was built.

01

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 predictable performance and safety.

02

Remix + JSX admin

Used the Shopify Remix app template with JSX views and Shopify Web Components for a fast, Shopify-native admin experience.

03

Composable rule engine

Modelled rules as location, product/tag, customer-tag, and order-value conditions that combine into include/exclude logic for any checkout scenario.

Tech Stack

The toolkit.

App
RemixReactJSXTypeScriptPolarisShopify Web Components
Checkout Logic
Shopify FunctionsRustCart & Checkout Validation
Shopify
Admin GraphQL APIApp BridgeMetafieldsWebhooks
Features Shipped

What's live.

Advanced location rules — country, province, region, postal code
Tag-based restrictions on products and customers
Order value conditions — min/max cart totals for COD
Complex include / exclude rule combinations
Shopify-native admin UI with no-code setup
Free plan and free trial on the Shopify App Store
Results

The outcome.

Live
On Shopify App Store

Published as COD Rules By Comeasy with free plan and free trial.

Rust
Shopify Function

Checkout validation runs as a Rust Shopify Function for safety and speed.

No-code
Merchant setup

Shopify-native UI lets merchants ship rules without developers.

24/7
Support included

Merchants get 24/7 support alongside the app.

In summary

Merchants now control Cash on Delivery at checkout with flexible, rule-based logic — reducing COD risk and RTOs without touching code, powered by a Rust Shopify Function and a Shopify-native admin built on Remix.