Custom Shopify Logistics App

Here is a complete, ready-to-use Project Brief / Scope of Work (SOW) written in clear, technical English. You can send this directly to Shopify developers or software agencies to get accurate quotes and proposals.

Project Brief: Custom Shopify Logistics Integration App
1. Project Overview
We are a third-party logistics (3PL) and fulfillment company looking to build a production-ready Shopify Public App.

The goal of this app is to serve as a seamless bridge between Shopify merchants and our Logistics Management System (WMS/TMS). Merchants should be able to install the app from the Shopify App Store, connect their account, and automatically outsource their fulfillment, shipping rate calculations, inventory management, and tracking updates to our network.

2. Core Features & Architecture
A. Merchant Interface (Frontend)
Design Standard: Must be built using Shopify App Bridge and Shopify Polaris UI for an authentic, native Shopify look and feel.

Onboarding & Authentication: Simple OAuth install flow. Merchants enter their account credentials/API key to connect their store to our logistics platform.

Settings Panel: Toggles for automatic vs. manual order sync, default package dimensions, and service-level mapping.

B. Shipping Rate Calculation (Checkout Integration)
Integration with Shopify’s Carrier Service API.

Dynamically fetch live shipping rates, delivery estimates, and service tiers from our system and display them at the customer’s Shopify checkout.

C. Order Management & Sync
Real-Time Webhooks: Utilize orders/create and orders/cancelled webhooks to instantly send new orders from the merchant’s store to our WMS/TMS.

Fulfillment Sync: Once an order is packed/shipped in our system, the app automatically calls Shopify's Fulfillment API to mark the order as fulfilled and attach the tracking number and carrier link.

D. Inventory Synchronization
Automatically sync stock levels from our warehouse to the merchant’s Shopify store via inventory_levels/set to prevent overselling.

3. Technical Requirements & Stack Preferences
Backend Framework: Node.js (Remix / Shopify App Template preferred) or Ruby on Rails.

API Standards: Shopify GraphQL Admin API & REST APIs (where applicable).

Database: Lightweight, high-performance database (PostgreSQL / Redis for caching) to handle high order volume seamlessly.

Security & Compliance: GDPR/CCPA webhooks implementation, secure token storage, and compliance with all Shopify App Store Partner guidelines.

4. Acceptance Criteria
Flawless Installation: The app installs and authenticates without errors on development and production stores.

Speed & Scalability: Dashboard loads in under 2 seconds, capable of processing 1,000+ orders daily per merchant without lag.

Reliable Webhooks: Webhooks handle order ingestion and tracking updates with a 99.9% success rate and proper retry logic.

App Store Ready: Code passes security standards and guidelines required for approval on the official Shopify App Store.

Handover: Full source code ownership, clear developer documentation, and a recorded video walkthrough.

5. Submission Requirements for Developers
Please reply with:

Your Choice of Tech Stack: (e.g., Remix + React + Polaris + PostgreSQL).

Estimated Timeline & Milestones: (e.g., Phase 1: Auth & Setup, Phase 2: Order Sync, Phase 3: Testing & App Store Submission).

Relevant Portfolio: Links or case studies of custom Shopify apps, fulfillment tools, or 3PL integrations you have built previously.