third-party logistics provider (3PL)
An outsourced logistics company. In ecommerce it usually means the outside warehouse that stores your stock and picks, packs, and ships your orders.
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What it is
A 3PL is a company you outsource logistics to. The full category is wide: warehousing, transportation and freight, customs and forwarding, distribution, and returns processing, and plenty of 3PLs never store a thing you own. In ecommerce the word has narrowed, and when a merchant says '3PL' they almost always mean an outsourced fulfillment provider: a company that holds your inventory and does the picking, packing, and shipping when orders come in. You send them pallets, they send your customers parcels. Well-known names: ShipBob, ShipMonk, Amazon FBA (a 3PL wearing a marketplace hat), and a long tail of regional warehouses that will happily take your stock.
Reach for one when packing orders on your kitchen table stops scaling, usually somewhere past a few dozen orders a day, or when you want stock in two countries so delivery is fast and duties are sane. The integration is the real product: your store pushes orders to them over API, they push back tracking numbers and stock counts, and a good 3PL keeps inventory synchronized so you never sell a phantom unit.
Gotcha: the quoted pick-and-pack rate is never the bill. Storage per bin per month, receiving fees, per-extra-item fees, long-term storage penalties, returns processing, and custom packaging surcharges all pile on. Ask for a sample invoice from a real client-sized account, not a rate card, and check how they handle a mis-pick before you sign.
Ask AI for it
Wire my store to a 3PL behind a typed FulfillmentProvider adapter with four methods: createFulfillment (line items, SKUs, quantities, shipping address, returns a provider fulfillment ID), cancelFulfillment, handleShipmentWebhook (writes carrier, tracking number, and tracking URL back onto the order and fires the shipping confirmation email), and fetchInventory (stock per SKU per warehouse, on a schedule, marking variants unavailable when the provider reports zero). Make every write idempotent on a provider event ID so a retried webhook never ships twice. If credentials and API docs for the named provider are available in this project, implement against their documented endpoints; if not, ship a sandbox adapter with realistic fixtures plus a clearly marked integration boundary listing exactly what a real provider must supply. Do not invent endpoint shapes.