Inventory how-to

How to set up a backup supplier

Set up a backup supplier by adding it as a second supplier record for the same SKU, with its own lead time, cost, and minimum order.

Short answer: Set up a backup supplier by adding it as a second supplier record for the same SKU, with its own lead time, cost, and minimum order. Use it when your primary supplier is late, out of stock, or raises minimums you cannot meet. Keep the backup's lead time and safety days accurate so reorder points stay correct even if you switch suppliers mid-cycle.

Why have a backup supplier at all

A single supplier is a single point of failure. If they run out of stock, raise their minimum order, or go quiet for a few weeks, you have no fallback until you find one in a hurry. Having a backup already set up, even for just your top sellers, means you can switch fast without losing sales.

What to record for each backup supplier

For every SKU, note the backup supplier's lead time (it is often longer than your primary, since you order from them less), their case pack size or minimum order quantity, and their cost. If their lead time is longer, your reorder point for that SKU needs to reflect whichever supplier you plan to use at the time you place the order, not always the primary.

When to actually use the backup

Common triggers: the primary supplier misses their promised ship date, they tell you a SKU is backordered, or their minimum order jumped past what you want to carry. Decide this on a per-SKU basis, not as a blanket swap. A backup supplier with a 45-day lead time is not a real backup for a fast seller you reorder every two weeks, it is only useful for slower movers where the longer wait does not create a stockout.

Keep both suppliers' data current

Update cost and lead time for both suppliers whenever they change, even if you are not currently using the backup. Stale lead time data on a backup supplier means that when you finally need it, your order-by dates will be wrong, which defeats the purpose of having a backup at all.

Step by step

  1. List which SKUs are critical enough to need a backup supplier, usually your top sellers or ones with long primary lead times.
  2. Find a second supplier for each of those SKUs and get their lead time, cost, and minimum order or case pack size.
  3. Record both suppliers against the SKU, with the primary marked as default.
  4. Set reorder points and safety days based on whichever supplier's lead time applies at order time.
  5. When the primary supplier fails to deliver or hits a limit, switch the purchase order to the backup and confirm the new lead time before approving.
  6. Review backup supplier details every few months so the data does not go stale.

Worked example

Say you sell a kitchen scale, SKU KS-100, at 4 units a day. Your primary supplier has a 14-day lead time and 5 days safety stock, so your reorder point is 4 x (14 + 5) = 76 units. Your backup supplier has a 25-day lead time and the same 5 days safety stock, giving a reorder point of 4 x (25 + 5) = 120 units. If the primary tells you they are backordered and you need to switch to the backup, you should already have at least 120 units on hand or on order, otherwise you will stock out before the backup's order arrives.

How SteadyShelf helps

SteadyShelf lets you set up more than one supplier per SKU with separate lead times and safety days, and will draft and email a purchase order to whichever supplier you choose for that order. It does not automatically decide when to switch suppliers or flag that a primary is underperforming, that judgment call is still yours.

$29/month flat, unlimited products and suppliers, 30-day free trial. Run the numbers now with the free reorder point calculator.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

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FAQ

Can I have more than two suppliers for one SKU?

Yes, there is no limit in principle, but most small stores only need a primary and one backup. Adding more suppliers than you actually use just adds upkeep without benefit.

Should the backup supplier's price match the primary's?

Not necessarily. Backup suppliers are often slightly more expensive or have higher minimums, since you buy from them less often. Treat the price difference as the cost of having a fallback, and factor it into your margin only for the orders you actually place with them.

Let SteadyShelf do this math for every SKU

Order-by dates per supplier, seasonal forecasts and draft POs for your Shopify store. $29/month after a 30-day free trial.

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