02Our Integration Process
From Channel Audit to Live Multichannel Sync in Five Steps
You see the exact sync architecture and allocation rules before development starts, not just a finished integration at the end.
05Projects We've Built
Ecommerce Projects We Have Built
A selection of Shopify and ecommerce builds shipped for clients, several involving multichannel and backend system integrations like this one.
Ready for one source of truth on stock? ⚡ Get a free consultation!
LET'S DISCUSS
06What Our Clients Say
What Clients Say After Launch
Feedback from ecommerce teams we have built multichannel and backend integrations for.
keep scrolling
We had a different kind of problem. People were visiting the store, adding products to their carts, and then disappearing before they finished the order. We had tried a few apps and made changes here and there, but nothing really seemed to solve the bigger issue. The team went through the shopping experience with us and pointed out things we hadn't really noticed ourselves. They cleaned up the cart and checkout flow, made the mobile experience much smoother, and helped us make the store feel easier to shop. I’m not going to pretend we fixed everything overnight, but it finally feels like the store is helping the sale instead of getting in the way of it.
Ethan Parker
Founder of Elite Academy
The mobile experience is probably my favourite part of the new site. We had spent a lot of time making sure the desktop version looked right, and the team kept pushing us to think about how everything would actually feel on a phone too. They were right. The navigation is clean, the interactions feel natural, and everything we’ve tested so far works exactly as it should. They also went through the links, forms, integrations, and other details more than once before launch, which I really appreciated. And even after going live, we could still reach out when something came up. The whole process felt friendly, organised, and surprisingly straightforward.
James Whitmore
Head of Marketing of Lumen Outdoor
We had a pretty specific idea of what we wanted our website to become, but I wasn’t sure how easily we could explain all of it to a development team. There were quite a few moving parts, and we were working toward a deadline, so I expected a few things to get lost along the way. That never really happened. They understood what we were trying to achieve, kept us updated throughout the process, and got everything ready within the agreed timeline. The final site feels much easier to navigate, works beautifully on mobile, and is noticeably smoother for our customers. It was a huge relief seeing the original idea actually turn into the website we had in mind.
Michael Bennett
Founder & CEO of Northbridge Consulting
150+
Projects shipped
10+
Years in development
Top 3%
Upwork Top Rated Plus
5★
Average review score
07Work Culture
Why Businesses Trust Us With Multichannel Inventory Sync
Getting this wrong means overselling or lost sales on real orders, so the architecture has to match your actual setup. These are the habits we bring to every project.
Architecture matched to your volume
Webhooks, polling, or middleware, recommended based on your actual order volume, not a default answer.
Allocation rules that hold
Priority waterfalls or shared-pool buffers protect wholesale and DTC commitments from marketplace demand spikes.
Built for channel outages
Retry logic and reconciliation passes catch anything a channel's API misses while it's down.
Tested against failure scenarios
We test allocation rules and simulated outages with real data before your live channels are connected.
Clear on what's included
You know exactly which channels, buffers, and allocation rules are covered before development starts.
Built to be maintained
Documentation and an optional retainer so the sync keeps working as each channel's API changes.
08Overview
Who builds custom multichannel inventory sync across Shopify, marketplaces, 3PL, and ERP?
DeveloperLook builds custom multichannel inventory sync connecting Shopify to your marketplaces, 3PL, and ERP, with webhook-driven or hybrid sync architecture and per-channel stock buffers or allocation rules that stop overselling. Projects start from $2,499, most complete in 3 to 8 weeks, and we scope the architecture to your actual order volume and channel mix.
- Service
- Custom multichannel inventory sync
- Starting price
- From $2,499 USD, fixed scope after a project brief
- Typical timeline
- 3 to 8 weeks
- Platform
- Shopify, Shopify Plus, plus your marketplaces, 3PL, and ERP
- Built with
- Webhooks, REST APIs, iPaaS middleware, Shopify Admin API
- Experience
- 10+ years and 150+ shipped projects
- Post-launch support
- 30 days included, then optional retainer
- Communication
- Calls in US, UK, and AU business hours
Who it's for
Stores selling across 3 or more channels
You're on Shopify plus a mix of Amazon, eBay, Etsy, Walmart, or wholesale, and single-channel connector apps don't cover the full picture.
Businesses hitting overselling across channels
You've had the same unit sell on two channels before a sync caught up, and need allocation rules or buffers that actually hold.
Stores combining marketplaces with 3PL or ERP fulfillment
Your inventory truth lives partly in a 3PL warehouse or ERP, and channel listings need to reflect that instead of just Shopify's own count.
Businesses evaluating sync architecture
You're not sure whether polling, webhooks, or middleware fits your order volume, or your current setup has too much lag.
Teams protecting specific channels or commitments
You need to protect wholesale or DTC stock from being consumed by faster-moving marketplace channels.
Not a fit for
You only sell on one channel, Shopify alone with no marketplaces or 3PL involved. A single-purpose service, or no integration at all, likely covers that.
You need a specific marketplace or system integration built rather than the full multichannel architecture. Our dedicated Amazon, eBay, Etsy, NetSuite, ERP, WMS, and 3PL integration services cover those individually.
You need order tracking pages for customers rather than backend inventory sync. That's a different, customer-facing service.
You're not on Shopify. This integration is Shopify-specific, and other platforms would need to be scoped separately.
11The Right Technology for Your Project
Technology Stack
We integrate through webhooks, REST APIs, and iPaaS middleware, matched to your channel mix and order volume.
No tools available for the selected category.
Book Your Exclusive Strategy Session Today!
Pick a 30-minute slot that works for you. We meet on Google Meet to align on goals, scope, and the right next step.
12FAQ
Frequently Asked Questions
Straight answers on multichannel inventory sync architecture, allocation, and overselling prevention.
How do I sync inventory across Shopify, marketplaces and my 3PL?
Each channel and your 3PL push or expose stock and order data through their own API, and the integration reconciles all of it against one source of truth, typically Shopify or your ERP, then pushes updated counts back out to every connected channel.
How real-time can multichannel inventory sync be?
Webhook-driven sync can update within seconds of a sale, which we recommend once you're past roughly 200 orders a day or selling across several channels. Lower-volume stores are often well served by scheduled polling every few minutes, which is simpler to maintain.
How do you stop overselling across channels?
We use per-channel safety buffers, listing slightly less than your true stock, or a priority allocation waterfall that protects wholesale and DTC commitments before marketplace demand consumes shared stock, combined with atomic stock decrements that stop two channels from claiming the same last unit.
What is the best architecture for multichannel sync (API, webhooks, middleware)?
Webhooks are the most reliable under load but more complex to build. A hybrid pattern, webhooks plus periodic reconciliation passes, is what most growing stores end up on. iPaaS middleware can be faster to set up but adds a subscription and less control than a direct integration.
How does Shopify Walmart integration handle stock and orders?
Walmart Marketplace's APIs use OAuth 2.0 and cover inventory updates by fulfillment center, item listings, and order retrieval and acknowledgment, so a Shopify integration maps your Shopify inventory and orders to Walmart's item and order structure the same way it would for Amazon or eBay.
How much does a custom multichannel sync cost?
Projects typically start from $2,499 for a straightforward multi-channel setup, and scale up with additional channels, high order volume needing webhook architecture, or complex allocation rules across wholesale, DTC, and marketplaces. You get a fixed quote after reviewing your channel mix.
How are stock buffers and reserves handled per channel?
Marketplace channels typically carry a larger buffer, roughly 7 to 14 days of average demand, since a marketplace stockout can hurt your search ranking there. DTC channels usually need less, and wholesale commitments are handled as hard reserves matching confirmed purchase orders rather than a percentage buffer.
What happens when one channel's API is down?
The integration queues affected updates with retry logic and exponential backoff, and a periodic reconciliation pass catches anything missed once the channel is back, rather than losing the update or requiring a manual fix.