Custom Shopify App developer

We are developing a Shopify app that enables merchants to manage affiliate marketing directly from their Shopify store while syncing data with our external platform, ShopLinky (our in-house affiliate management system).

Merchants who use Shopify will be able to:
Connect their Shopify store with their ShopLinky brand account.
Generate and manage affiliate/referral links.
Track affiliate-driven sales, commissions, and payouts.
View affiliate analytics inside ShopLinky’s dashboard.

We already have ShopLinky running as a separate web application with its own backend and APIs.
Your job is to build the Shopify app and handle the integration between Shopify and ShopLinky.

Core Requirements:
Shopify App Development
Develop a public Shopify app (embedded in Shopify Admin).
Implement OAuth 2.0 authentication for store installation.

Use Shopify Admin API / GraphQL API for:
Reading products and orders.
Managing metafields, tags, and custom data.
Registering and handling webhooks (orders/create, app/uninstalled).
Use Polaris UI + App Bridge for the embedded admin interface.

Integration with ShopLinky:

Connect the app to ShopLinky APIs (we’ll provide API documentation).

Sync:
Products → ShopLinky (for affiliate link creation).
Orders → ShopLinky (for tracking affiliate conversions).

Handle real-time sync via Shopify webhooks.
Map each connected Shopify store to a ShopLinky brand account.

Affiliate Logic:
Capture affiliate/referral data via URL parameters (e.g., ?ref=affiliate123).
Record affiliate-driven sales and commissions in ShopLinky via API.
(Optional) Tag Shopify orders with affiliate metadata.

Technical Stack (Recommended):
Frontend: Next.js + Shopify Polaris + App Bridge
Backend: Node.js (Express or NestJS)
Database: PostgreSQL or MongoDB
APIs: REST or GraphQL
Hosting: AWS
We’re open to other technologies if justified.

Deliverables:
Fully functional Shopify app ready for public listing.
Secure OAuth installation flow.
Data sync and webhook system (orders, products).
Integration layer with ShopLinky API.
Clean and responsive embedded dashboard (Polaris UI).
Documentation for setup and deployment.
Assistance with Shopify App Store review and publishing.

Skills Required:
Proven experience building Shopify public apps.
Strong knowledge of Shopify APIs, OAuth, and webhooks.
Experience with React / Next.js and Polaris UI.
Backend API integration experience (Node.js preferred).
Understanding of affiliate or referral systems is a plus.

Additional Info:
You will collaborate with our internal team managing the ShopLinky backend.
ShopLinky’s API documentation and mock data will be provided.
We prefer developers who can communicate clearly, provide regular updates, and are familiar with Shopify app submission best practices.