How to sync inventory across Amazon, Walmart and Shopify
To sync inventory across Amazon, Walmart and Shopify, keep one central stock count and connect all three stores to it through their APIs. Give each product one SKU everywhere, and reserve stock when an order comes in. Hold a small buffer for checkout spikes, so one sale updates every channel.
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Quick answer
Use one system as the source of truth for stock, connect Amazon, Walmart, and Shopify to it by API, standardize SKUs, and set rules for when stock is reserved, deducted, and reconciled. Multichannel tools such as Goflow, Linnworks, and Sellbrite all sell this sync; Goflow’s free Core plan covers all three channels up to 500 orders a month.
Affiliate disclosure. Mishal Brands is in the Goflow partner program, and this page contains referral links to Goflow. If you sign up through one of those links, Mishal Brands may earn a commission, at no extra cost to you. This page does not guarantee sales, savings, or any other result. Affiliate disclosure.
Facts about Goflow come only from goflow.com, and facts about other vendors only from their own websites, all checked October 13, 2026. Mishal Brands has not tested Goflow or the other tools here, so this page reports what each vendor publishes, not hands-on results.
Why does inventory get out of sync?
Because each channel keeps its own count, and updates arrive late. Goflow’s inventory sync guide describes how small delays “stack up under pressure,” so one unit can be sold on one channel while still showing as available on another.
At low volume the gap rarely matters. As orders speed up, overlapping checkouts turn the gap into oversells, refunds, and marketplace penalties.
How do you set up inventory sync, step by step?
Pick one source of truth, match your SKUs, connect each store by API, and set update rules. The steps below follow Goflow’s guide and apply whichever tool you use.
- Choose one central inventory system. Replace three separate counts with “one master stock count, one set of rules,” as Goflow’s guide puts it. That can be an order or inventory management platform.
- Standardize SKUs. Give each product one identifier on every channel. Goflow names inconsistent SKUs as the cause of shipping the wrong variant.
- Connect each store by API. Goflow’s guide lists the method for each: Amazon through API credentials and tokens, Walmart through client credentials, and Shopify through OAuth.
- Set update rules. Reserve stock at checkout, deduct it when payment completes, and reconcile when the item ships. Deducting only at shipment oversells during spikes; deducting too early blocks real sales.
- Hold buffer stock. Keep a safety margin per channel for checkouts that happen at the same time, since carts do not reliably hold stock across platforms.
- Plan for failures. The guide lists delayed API responses, duplicate messages, failed syncs, and outages as cases a sync setup must survive.
How does each channel connect?
Each platform uses its own credentials, per Goflow’s guide. Fulfillment networks such as FBA and WFS hold their own stock, so treat that inventory separately from your warehouse.
| Channel | Connection method | Fulfilled by the channel |
|---|---|---|
| Amazon | API credentials and tokens | Amazon FBA |
| Walmart | Client credentials | Walmart Fulfillment Services (WFS) |
| Shopify | OAuth access | Shopify POS orders are counted with channel-fulfilled orders in Goflow’s billing |
What tools can sync inventory across these channels?
Multichannel inventory platforms do this as their main job. Goflow says it updates listing quantities on each store from your allocation rules, including warehouse and vendor stock, on its listings page. Linnworks says it can “sync inventory instantly across 100+ channels” on its pricing page, and Sellbrite lists multi-channel inventory control on its pricing page.
Comparisons: Goflow vs Linnworks and Goflow vs Sellbrite.
Can you sync Amazon, Walmart, and Shopify for free?
With Goflow, yes, up to 500 orders a month. Goflow Core is free and connects Amazon, eBay, Shopify, TikTok, and Walmart. Sellbrite’s free plan allows 30 orders a month.
Above 500 orders, Goflow’s paid plans start at $499 a month. Details are on the Goflow free plan page.
How do you try Goflow?
Start on the free Core plan, or request a demo to see the full platform. Goflow says most accounts are live in a few days and that onboarding is included at no extra charge.
Referral link. The button below is a Goflow partner referral link and opens Goflow’s demo request page. Mishal Brands may earn a commission if you sign up.
More on Goflow: Goflow review, Goflow vs Linnworks, Goflow vs Sellbrite, Goflow free plan (Goflow Core), Goflow integrations.
FAQ
What is the best way to prevent overselling on Amazon, Walmart and Shopify?
Keep one central stock count connected to all three stores, reserve stock as soon as an order comes in, and hold a small buffer for simultaneous checkouts. Goflow’s guide recommends this setup.
Do I need software to sync inventory across channels?
For more than a handful of orders, yes in practice. Manual updates cannot keep up with simultaneous sales, which is how oversells happen. Tools such as Goflow, Linnworks, and Sellbrite automate the sync.
How should FBA inventory be handled?
Amazon holds FBA stock in its own network, so track it separately from the stock in your warehouse. Goflow counts channel-fulfilled orders such as FBA as half an order, and Sellbrite offers an FBA inventory add-on.
How often should inventory sync?
As close to real time as possible. Goflow’s guide describes real-time sync as an update across all channels the moment a sale happens, rather than a batch every 5, 15, or 30 minutes.
Can I sync inventory across Amazon, Walmart and Shopify for free?
Yes, with Goflow Core, for up to 500 orders a month. Core connects Amazon, eBay, Shopify, TikTok, and Walmart with no credit card.
Mishal Brands is an independent review site. Goflow links on this page use the referral link https://ps.goflow.com/ddfwzn294dqe from the Goflow partner program, including source links. Signing up can earn Mishal Brands a commission. Links to other vendors are plain links. Affiliate disclosure.
Sources, checked October 13, 2026: Goflow inventory sync guide; Goflow listings; Goflow pricing; Linnworks pricing; Sellbrite pricing. Prices and features can change; if this page disagrees with a vendor’s site, the vendor’s site is right.