Storefront and carrier integrations for 3PLs: what to check

A storefront integration moves orders into your warehouse system, stock levels back to the store, and tracking numbers back to the order. A carrier integration prints labels and sometimes compares rates. When these connections work, nobody notices. When they fail, clients notice within the hour, usually because a shopper wrote to them asking where the parcel is.

This page covers the five jobs these integrations do, how each fails, and what to ask before promising a client a connection.

The five jobs

1. Order import

New orders flow from the store into your system with the shipping address, line items, shipping method chosen and any gift or special notes.

What to check:

• How often orders are pulled or pushed. A few minutes of delay is normal. Hours is not.
• Whether each client has their own connection, tied to their own account in your system.
• What happens to an order with an unknown SKU. It should stop and show an error, not vanish or ship the wrong item.
• Whether the shipping method on the store maps to a carrier service you actually use.

SKU mapping is where onboarding goes wrong. The store says "BLUE-M" and your system has "BLU-MED". Agree on one identifier per product before the first order, and record it in the client setup.

2. Stock sync

The store needs to know how much it can sell. Your system knows what is in the building.

Decide which quantity you send: on hand, or on hand minus what is already allocated to open orders. Sending on hand overstates stock and leads to oversells. Most 3PLs send available stock, which is what is left after allocations.

Also decide how often. Syncing after every transaction costs more calls but keeps the store close to reality. Syncing on a schedule is simpler but leaves gaps, and a popular item can sell out between updates.

If the client has stock in more than one place, say whether you are sending only your warehouse's quantity or a total. Mixing these up causes oversells.

3. Tracking write back

Once a label is created, the tracking number and carrier go back to the store so the shopper gets a shipping email. This is the step shoppers see.

Check that it works for split shipments, where one order ships in two parcels, and that a voided or reprinted label does not leave a dead tracking number in the store.

4. Label printing and carrier accounts

Your system asks the carrier for a label, prints it, and records the cost. Questions to settle:

• Whose carrier account is used: yours, the client's, or both depending on the client?
• Does the label cost land on the right client's invoice automatically?
• What happens if the carrier's service is down? Can you still pack and hold orders?
• Does the system check an address before a label is bought? Fixing an address afterwards can cost more than the check would have.

Carrier cost is a pass through, so record it per order. The way to show it on an invoice is in per order fulfillment fees explained.

5. Rate shopping

Rate shopping compares services for each parcel and picks one by your rules. A simple rule is "cheapest service that arrives by the promised date." More complex ones weigh carrier contracts, zones and weight bands.

Test it with real parcels: a small light one, a heavy one, and one going to a remote address. Check that the service chosen matches the shipping method the shopper paid for. A shopper who paid for two-day delivery should not get the cheapest ground option because the rule only looked at price.

How integrations fail

Platforms change their interfaces, credentials expire, and client staff change settings without telling you. Typical failures:

• Orders stop arriving because a connection was reauthorized and the token lapsed.
• Duplicate orders appear after a retry.
• Tracking numbers fail to post because the order was edited in the store.
• Stock in the store drifts away from yours after a bulk adjustment.

You cannot prevent all of these. You can make them visible. Your software should give you:

1. An error list showing which orders or updates failed and why.
2. A retry action for a single item or a batch.
3. An alert when a connection has not received an order in longer than usual for that client.
4. A log that shows what was sent and received, so you can settle a dispute.

Then assign someone to check the error list every morning. A list nobody reads is the same as no list.

What EDI is, and what it is not

Larger retail customers often want EDI rather than a storefront connection. It follows different rules, with strict labels and message formats. If a client asks for it, read EDI for 3PL fulfillment: the basics before you quote.

Questions to ask a vendor

1. Which storefronts and carriers does it connect to today, and which are on a list for later?
2. Is the connection included in the subscription, or charged per client or per connection?
3. How does a client authorize their store, and how do I see that the connection is healthy?
4. What happens to orders while a connection is down?
5. Who fixes it when a platform changes, and how fast?
6. Can I see a log for any one order?

Next step

Take your busiest client and trace one order from the store to the doorstep. Write down every system it touched and where a person had to step in. Each manual step is a place an integration could help, and each automatic one is a place it could fail quietly.

Questions people ask

What does a storefront integration do for a 3PL?

It brings the client's orders into your system, sends stock levels back to the store, and writes tracking numbers to the order once it ships. Some also handle cancellations and address changes.

What is rate shopping?

Rate shopping compares the cost and transit time of several carrier services for one parcel and picks one by your rules, such as cheapest that meets the promised delivery date.

What happens when an integration fails?

Orders can stop arriving, tracking can fail to reach the shopper, or stock can drift from the store. You need a visible error list, a way to retry, and an owner who checks it every day.

Should a 3PL build its own integrations?

Most buy them as part of fulfillment software. Building and maintaining each connection takes ongoing work because platforms change their interfaces, so count that cost before deciding.