Switching fulfilment providers goes wrong at the inventory transfer, not at the contract. A clear migration sequence, a decision between parallel running and a hard cutover, and honest customer messaging keep orders flowing. This guide covers the signals to switch, where risk concentrates, and what to tell customers.
Most sellers change provider because something has already gone wrong: late dispatches, rising costs, or poor visibility. The switch itself can cause a second round of damage. Treat it as a planned project, not a flip of a switch, to protect revenue during the move.
What Signals Tell You It Is Time to Switch?
One bad week isn’t a reason to move. A pattern is. Repeated missed cut-offs, pick errors above one in 200 orders, surcharges that were never explained, and stock counts that do not match your own records are the usual triggers. Capacity problems at peak and slow responses from the account team are others.
Before committing to a move, many sellers compare what eCommerce fulfilment providers actually offer against what their current contract delivers. Write down that comparison, because it becomes the specification for the replacement and the benchmark for judging it later.
The table below summarises the common signals and the evidence worth gathering for each.
|
Signal |
Evidence to collect |
Why it matters |
|
Missed dispatch times |
Order timestamps for the last three months |
Shows whether the issue is occasional or systemic |
|
Pick and pack errors |
Error count against total orders |
Gives a measurable accuracy rate |
|
Stock mismatches |
Monthly count against your own records |
Points to a data or process fault |
|
Unexplained charges |
Invoices matched to the rate card |
Reveals contract drift |
Once you have the evidence, the question becomes how to move without losing orders, and that’s where the sequence matters.
Where Does Risk Concentrate in a Migration?
The inventory transfer is the dangerous stage. Stock is in a lorry, in neither warehouse’s system, and cannot be sold. Receipt at the new site then takes days, and count or labelling errors appear only when orders start to fail.
Three other points carry risk. Integration is the first: the new provider must connect correctly to your store and marketplaces, with stock levels mapped to the right products. The second is the order-routing cutover, where orders can fall between systems. The third is returns in transit, since parcels sent back to the old address during the switch are easily lost.
A safe sequence usually runs in this order:
Each step includes a check before the next begins, which keeps a small error from becoming a large one. The next question is whether to run both providers at once.
Should You Run in Parallel or Cut Over Hard?
Running in parallel means holding stock at both sites for a period and splitting orders between them. It costs more because you pay for two sets of storage and handling, and you have to allocate stock between locations. In return, if the new provider has problems, the old one is still there.
A hard cutover moves everything on one date. It is cheaper and simpler to manage, but any failure affects every order at once. It suits small catalogues, low order volumes, and quiet periods.
For most sellers, a phased approach sits in between. Start with a small group of products or one sales channel, then widen. This is also a good moment to look at how fulfilment fits with the wider customer promise, and a piece on transforming customer experience through services, branding and marketing is a useful reminder that delivery is part of the brand, not separate from it.
Whichever route you choose, avoid switching in October to December. A migration at peak leaves no room for error, and January or the summer lull are far safer.
What Should You Tell Customers, and When?
Most customers never need to know which warehouse ships their order. They need to know delivery will be on time and that you’ve handled anything unusual. Tell them only what affects them.
If delivery times will change during the move, say so on the product page and at checkout, with a clear date range. If branded packaging or return addresses are changing, update the order emails and any printed inserts before the first parcel leaves the new site. A short notice to customers with open returns prevents parcels from going to the wrong place.
Prepare your support team with a simple brief: what is changing, the dates, and how to answer questions. Keep a log of issues during the first two weeks, because patterns show up quickly and are far easier to fix early.
Frequently asked questions
How long does a fulfilment switch take?
Four to twelve weeks is typical, depending on catalogue size, integration work, and the notice period in your current contract.
Will customers notice the change?
Usually not, if you manage the move well. The visible effects are delivery times, packaging, and return addresses.
Should I switch during peak season?
No. Peak leaves no room for error, so a quieter period, such as January or summer, is much safer.
What is the biggest risk when switching?
Inventory transfer: if stock cannot be sold, counts can go wrong. Verify quantities on receipt before routing orders.
Can I stay with two providers permanently?
Yes, some sellers keep two for resilience or regional coverage. It costs more and needs clear rules for stock allocation.