What Is a 3PL? Third-Party Logistics, Explained

A 3PL (third-party logistics provider) is a company that handles logistics for other businesses. It stores goods, ships them, and fulfills orders on your behalf, so you outsource the warehouse and transport instead of running them yourself.

A 3PL takes over some or all of the physical supply chain. Typical services include warehousing, transportation, order fulfillment, freight forwarding, and returns handling. A growing online retailer might send its whole inventory to a 3PL, which then picks, packs, and ships each order as it arrives, alongside goods for dozens of other clients.

The model scales up. A 4PL (fourth-party logistics provider) manages the entire supply chain and coordinates several 3PLs, often without owning trucks or warehouses of its own. Where a 3PL moves the boxes, a 4PL runs the network above them.

For a smaller business, a 3PL trades fixed cost for variable cost: no lease, no forklift, no warehouse staff, just a bill per order handled. The trade-off is visibility. Your stock now sits in someone else's building, run by someone else's software, and you see only what they choose to show you.

That visibility gap is usually a data problem. A 3PL sends stock counts and shipment statuses through EDI or an API; the retailer needs those feeds inside its own ERP and storefront to keep customers informed.

Why it matters for custom software

Working with a 3PL rarely fails on the warehousing; it fails on the integration. Off-the-shelf connectors assume a standard setup, and 3PL feeds rarely are one. We build the middle layer in our logistics software work, mapping a provider's data into the systems you already run so orders and stock stay in sync without anyone retyping them.