A 3PL (third-party logistics provider) is a company that handles warehousing, order fulfillment, prep, and shipping on behalf of other businesses. They own or lease warehouse space and provide labor, equipment, and carrier relationships.
You need a 3PL when self-fulfillment is either too expensive, too slow, or too far from your supply chain entry point. For most e-commerce brands, that threshold hits somewhere between 300 and 1,000 orders per month.
3PLs also make sense when you need specific capabilities — Amazon FBA prep, port pickup, international shipping, or same-day dispatch — that are difficult to build in-house.
The key question is not whether to use a 3PL, but which one fits your volume, channels, and inbound freight lanes. A 3PL near a port with same-day dispatch is a different product than a generic suburban warehouse.