Shopify app & API Integration.
Shopify custom app development and the integrations that connect Shopify to the rest of your business. ERP, CRM, OMS, PIM, custom workflows, real-time sync, and middleware. Built to be reliable, observable, and honest about what happens when something fails.
Years of Integration
Custom Apps Shipped
SKUs Synced via ECX
Middleware Uptime
Integration is where the rubber hits the road.
Resilient by design.
Integrations break. ERPs go down. APIs change. We architect with queueing, idempotency, retries, and observability from day one — so when a system fails (and it will), the customer never sees it and your team gets the alert before it’s an incident.
Custom, not bolt-on.
Stock Shopify apps are great until they’re not. When the third-party app charges per-order, makes its own assumptions about your data model, or doesn’t support your edge case, you end up building around it. We build apps that fit your workflow, not the average Shopify merchant’s.
ECX middleware platform.
Our ECX (E-Commerce Exchange) platform is the middleware backbone for our most complex integrations. Built and refined over a decade of ERP work: queueing, retries, transformation, mapping, audit logs, and dashboards. The hard part of integration is solved before we write the first line of your project code.
25+ years of ERP work.
Founded in 1998. We’ve integrated ecommerce with NetSuite, SAP, Microsoft Dynamics, AS400, Sage, Brightpearl, Acumatica, and a long list of custom in-house systems. The ERP team your CFO mentioned isn’t a new challenge for us; it’s the work.
The full integration stack.
From custom apps to webhook pipelines to enterprise middleware. The work we do most.
Custom Shopify Apps
Private apps built for your store: custom promotions, gift-with-purchase engines, loyalty tiers, returns flows, internal merchandising tools. Built on Shopify’s modern app framework with App Bridge, Polaris, and the GraphQL Admin API.
ERP Integration
NetSuite, SAP, Microsoft Dynamics 365, AS400, Sage, Acumatica, Brightpearl, and custom in-house ERPs. Real-time bi-directional sync for inventory, pricing, products, orders, customers, and fulfillment. Built to survive ERP downtime gracefully.
CRM Integration
Salesforce, HubSpot, Klaviyo, ActiveCampaign, Iterable. Bi-directional customer sync, segment mapping, lifecycle event passing, and the campaign attribution wiring most stacks miss. Includes Klaviyo back-in-stock and coming-soon flow setup.
OMS / PIM Integration
Order management (ShipStation, ShipBob, ShipHero, Cubbo, direct-to-warehouse) and product information management (Akeneo, Plytix, Salsify, custom PIMs). The hub-and-spoke layer that keeps every channel agreeing about what’s in stock.
Shopify GraphQL Admin API
All new integrations built on GraphQL Admin API: single-roundtrip nested queries, lower API cost, and on Shopify’s actively-invested-in track. Migration plans for legacy REST integrations as a discrete project.
Webhook & Event Pipelines
Real-time event-driven architecture: Shopify webhooks consumed reliably (HMAC verification, retry handling, dead-letter queues), routed to downstream systems, ERP, warehouse, finance. No silent webhook drops.
Middleware (ECX Platform)
For complex multi-system integrations, our ECX (E-Commerce Exchange) middleware: queueing, retries, idempotency, transformation, mapping, audit logs, observability dashboards. The hard part of integration, productized.
Automation Workflows
Shopify Flow workflows, custom Functions for backend logic, and external automation (Zapier, n8n, custom). Tagging, fraud flags, restock alerts, marketing triggers, and back-office routines connected end to end.
Payment & Financing APIs
Custom payment provider integrations, financing platforms (Affirm, Klarna, Afterpay, custom BNPL), wallet integrations, and B2B payment terms wiring. For enterprise brands with custom payment workflows, not the default Shopify Payments path.
Custom apps we’ve built.
Real production apps running on real enterprise brands. Two examples that came directly out of client integration work.
Custom Promotions App · 5 International Stores
Chantecaille — Multi-Region Promotions App
Custom Shopify app powering gift-with-purchase, free samples, discount code distribution, and special-pricing cross-sells across five international Shopify Plus stores. Multi-currency rules, regional scheduling, and per-store promotion catalogs from a single admin.
Also: custom speed-optimized JavaScript mini cart, ERP integration for inventory and order management, Klaviyo back-in-stock and coming-soon flows, Yotpo loyalty and reviews, phone-based checkout authentication, and Tableau reporting integration.
B2B Portal · ERP Sync · 50K SKUs
QC Supply — B2B Pro Portal & ERP Middleware
Custom B2B Pro Portal app: multi-user company accounts, role-based permissions, location-based ordering, and customer-specific catalogs on top of Shopify’s native B2B features. Built for a 50,000-SKU wholesale operation migrated off Magento.
Plus a Node.js middleware layer connecting Shopify’s GraphQL Admin API to QC Supply’s backend, replacing a legacy ERP sync that failed 12% of the time with real-time bi-directional inventory, pricing, and order sync.
Our apps on the Shopify App Store.
Two public Shopify apps published by ECommerce Partners. Available to any Shopify or Shopify Plus merchant.
B2B Buyer Portal
True self-service for wholesale customers. Company contacts add and remove users, manage shipping locations, assign custom roles, and track activity, all without filing support tickets with your team. Built for Shopify Plus B2B.
Smart Product FAQ & Schema
Auto-generates product FAQs using AI and injects FAQPage JSON-LD schema so your products show up in Google rich results and AI search. Customizable accordion display, no coding required.
Brands where Shopify is one of many systems.
ERP-Backed Operations
Brands running NetSuite, SAP, Microsoft Dynamics, AS400, or in-house ERPs. The integration is the project — the storefront is the easy part.
B2B + DTC Operators
Wholesale and direct-to-consumer from one Shopify Plus org. Customer-specific catalogs, payment terms, multi-user companies, and per-account pricing wired into your sales workflow.
Hitting App Limits
You’ve stacked 30 Shopify App Store apps and now they fight each other. Per-order fees are stacking. The promotion engine doesn’t support your edge case. Time for custom.
Fragile Batch Sync
CSV-based syncs running overnight. Inventory discrepancies, oversells, support tickets. Time to replace the batch pipeline with real-time event-driven sync that doesn’t fail silently.
How an integration project actually goes.
Integration is where projects slip. Here’s the shape of one that doesn’t.
Discovery & Contract
2-3 weeks. We map every entity that needs to flow: products, inventory, pricing, customers, orders, fulfillment. Output: a written integration contract — which way each entity syncs, at what frequency, and what happens when either system is down.
Architecture & Design
Technical architecture: API surfaces, webhook topology, middleware design, queueing, retry policy, observability plan. Plus admin UI design for custom apps. Reviewed with your engineering, ops, and finance teams before code is written.
Build & Stage
Custom app development, ECX middleware configuration, ERP/CRM/OMS integration, webhook pipelines. Staged in a non-prod environment with synthetic load tests for failure modes (ERP down, rate-limited, slow response).
Launch & Monitor
Phased cutover, observability dashboards, alerting wired to your team. Post-launch, we’re still on the integration: most clients stay on retainer for ongoing app development and integration support for years.
When to install, when to build.
Most stacks need both. Knowing which problem deserves which solution is half the integration work.
| Consideration | App Store App | Custom App |
|---|---|---|
| Upfront cost | $0–$500 install | $20K–$150K+ |
| Ongoing cost | $30–$2K/mo, often per-order | Hosting + maintenance only |
| Time to launch | Same-day install | 8–20 weeks |
| Fit to your workflow | Built for the average merchant | Built for yours specifically |
| Data ownership | Vendor holds the data | You own it |
| Customization | Whatever the vendor exposes | Anything you can describe |
| Risk of deprecation | Vendor pivots or shuts down | Yours; you decide its lifespan |
| Best for | Standard workflows, fast launch | Differentiated workflows, scale |
The honest version: App Store apps exist for a reason. For standard workflows — reviews, basic loyalty, email capture, shipping rate calculations — a $30/mo app from a reputable vendor is the right answer. Building custom for those would be expensive theater.
Custom becomes the right answer when one of three things happens: the workflow is unique to your business and no off-the-shelf app fits, the per-order or per-user pricing of the App Store option is going to cost you more than the build every year, or you’ve stacked so many third-party apps that they fight each other and the storefront slows down. Every brand at scale eventually has at least one of those moments.
The work we like best is the conversation about which side of the line each problem falls on. Bringing a list of “everything we want to fix” into a discovery call — and walking out with a sorted list of “install this app, build this app, ignore this for now” — is itself a deliverable.
Questions we hear from integration prospects.
What is the difference between a custom Shopify app and a Shopify App Store app?
A Shopify App Store app is a public, multi-tenant product built by a third-party developer for thousands of merchants. A custom Shopify app is built for one store (or one organization), tailored to that brand’s specific workflows, integrations, and data. App Store apps are faster and cheaper to start; custom apps give you exact-fit behavior, full control of the data, and no per-seat or per-order fees stacking up as you scale. Most enterprise brands use a mix of both. See the comparison above for the full breakdown.
How long does a Shopify ERP integration take?
A standard ERP integration with a well-documented modern ERP (NetSuite, recent SAP, Microsoft Dynamics) typically takes 8-14 weeks. Integrations with older or custom systems (AS400, legacy in-house ERPs, undocumented APIs) typically run 14-24 weeks. Every integration project starts with a 2-3 week discovery phase that produces a written integration contract: which entities sync, in which direction, at what frequency, and what happens when either system is down.
What does a custom Shopify app cost?
A focused custom app for a single workflow (a custom GWP engine, a specialized loyalty tier, a custom returns flow) typically runs $20,000-$60,000. A larger custom app with admin UI, multi-store support, and tight ERP integration typically runs $60,000-$150,000. Full integration projects with custom apps, middleware, and ERP sync as part of a Shopify Plus build run $80,000-$300,000+ depending on complexity. Every project starts with a paid discovery phase that produces fixed-bid pricing.
Which ERPs and business systems have you integrated with Shopify?
NetSuite, SAP, Microsoft Dynamics 365, Microsoft Dynamics NAV/AX, AS400 / IBM iSeries, Sage, Acumatica, Brightpearl, and a long list of custom in-house ERPs over 25+ years. On the CRM side: Salesforce, HubSpot, Klaviyo, ActiveCampaign. On the PIM side: Akeneo, Plytix, Salsify, and custom PIMs. On fulfillment/OMS: ShipStation, ShipBob, ShipHero, Cubbo, and direct-to-warehouse integrations.
How do you handle the case when our ERP goes down?
Resilient integrations assume both systems will fail at some point. We architect the middleware layer with queueing (so orders don’t drop when the ERP is unreachable), idempotency (so a retry doesn’t double-charge or double-ship), and observability (so you know when sync is degraded before customers notice). When QC Supply migrated, their legacy ERP sync failed 12% of the time; the Node.js middleware layer we built replaced it with real-time bi-directional sync that’s been stable for years.
Should we use Shopify’s REST Admin API or GraphQL Admin API?
GraphQL Admin API is now the default and the one Shopify is actively investing in; REST is being progressively deprecated. We build all new integrations on GraphQL Admin API for better performance (single round-trip for nested data), lower API cost (only fetching what you need), and a clearer migration path. For legacy integrations still on REST, we plan and execute the GraphQL migration as a discrete project.
Can custom apps be deployed across multiple Shopify stores in a single organization?
Yes. For Shopify Plus orgs with multiple stores (Shopify Markets, separate regional stores, B2B+DTC splits), we build custom apps to be multi-store from the start: shared backend, per-store configuration, centralized observability. Chantecaille’s custom promotion app runs across 5 international Shopify Plus stores with separate currency, scheduling, and promotion rules per region.
Do you publish public Shopify App Store apps too, or only custom?
Both. The majority of our work is custom apps for individual brands, but we also publish two public apps on the Shopify App Store: the B2B Buyer Portal ($39/month, 30-day free trial), which gives wholesale customers true self-service for users and locations on Shopify Plus B2B, and Smart Product FAQ & Schema (free plan, paid from $14.99/month), which auto-generates product FAQs with AI and injects FAQPage JSON-LD for Google rich results and AI search visibility. Having both perspectives means we can tell you honestly when an App Store app solves your problem and when you genuinely need custom.
Let’s map your integration.
Whether it’s a single custom Shopify app, an ERP integration that’s been on the roadmap for two years, or a full middleware build connecting Shopify to a dozen systems, start with a no-pressure conversation about the entities, the failure modes, and what success actually looks like.