DTC Brands Expanding to Amazon

The Moment Everything Gets Complicated

You have been running your DTC brand on Shopify. One warehouse, one channel, one set of numbers. You know your best sellers, your reorder cadence, your suppliers. Things work.

Then you launch on Amazon.

Suddenly you have two demand signals pulling from the same inventory pool. FBA wants 500 units sitting in their warehouse. Your Shopify customers need those same units available to ship from yours. Your supplier lead time has not changed, but the math has - you are now forecasting for two channels with different velocity profiles, different seasonality, and different fulfillment models.

I have watched this transition break otherwise well-run brands. Not because Amazon is hard, but because the inventory planning they had been doing for one channel does not scale to two.

Two Channels, Two Fulfillment Models

This is what makes multi-channel different from just "selling in more places."

	Shopify DTC	Amazon FBA
Fulfillment	You ship (or your 3PL does)	Amazon ships from their warehouse
Inventory location	Your warehouse	Amazon fulfillment centers
Restock trigger	Running low at your warehouse	Running low at FBA
Lead time	Supplier to you	Supplier to you, then you to Amazon
Penalty for stockout	Lost sales	Lost sales + ranking drop + buy box loss

That second lead time is the killer. On Shopify, you order from your supplier and stock arrives at your warehouse. Done. On Amazon, you order from your supplier, receive at your warehouse, prep the units, ship to FBA, and wait for Amazon to receive and stow them. That adds 1-3 weeks to your effective lead time.

If your reorder point does not account for that extra leg, you will stock out on Amazon while sitting on plenty of warehouse inventory. I have seen it happen to brands doing $50K/month on Amazon. The inventory existed. It was just in the wrong place.

The Split Allocation Problem

Here is the scenario that keeps DTC-to-Amazon founders up at night:

You have 2,000 units in your warehouse. Amazon FBA has 400 units left - about 18 days of supply. Your Shopify store is selling 30 units a day. A PO for 3,000 units arrives in 3 weeks.

How many of those warehouse units do you send to FBA right now?

Send too many, and your Shopify store stocks out before the PO arrives. Send too few, and Amazon stocks out, your ranking drops, and it takes weeks to recover. The answer depends on your safety stock at each location, the velocity on each channel, and how much risk you are willing to take.

This is not a spreadsheet problem. It is a system problem.

How ReplenishRadar Handles the Expansion

We built multi-channel into the core of the product, not as an add-on. When you connect both your Shopify store and your Amazon account, here is what changes:

Your inventory view shows stock across every location - warehouse, FBA, in-transit to FBA, in-transit from supplier. One number tells you total inventory. The breakdown tells you where it is.

Forecasting runs independently per channel. Your Shopify demand model and your Amazon demand model are separate because the buying patterns are different. Amazon might spike during Prime Day while your Shopify store spikes during your own sale events. But your reorder recommendations combine both forecasts, because your supplier does not care which channel the units are for.

Transfer alerts fill the gap between channels. When FBA inventory drops below your threshold, you get a specific alert: send X units by Y date. The calculation accounts for the time it takes to prep, ship, and have Amazon stow the inventory. Not just "FBA is low" - an actual number and deadline.

The First 30 Days

Most DTC brands adding Amazon follow this path:

Week 1: Connect both stores. ReplenishRadar imports your Shopify catalog and Amazon listings, matches SKUs, and pulls order history from both channels.

Week 2: Initial forecasts generate. You will see separate demand curves for each channel and a combined view. Your reorder points now reflect total demand, not just Shopify volume.

Week 3-4: Transfer suggestions start appearing based on your actual FBA sell-through rate. This is when the system earns its keep - telling you to send 300 units to FBA before you would have noticed the need yourself.

The whole setup takes about 10 minutes of active work. The rest is waiting for data to accumulate and forecasts to calibrate. Start a free trial and connect both stores on day one.

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Learn More:

• Multi-Channel Inventory Challenges - The 5 problems every multi-channel seller faces
• Amazon FBA Restock Strategies - Get your FBA timing right
• Multi-Channel Inventory Planning - Full overview of our multi-channel features
• Stockout Cost Calculator - What running out actually costs you