3PLSmart
3PL WMS/Inventory Management
3PL Inventory Management

Inventory management built for multi-client 3PL warehouses

Manage customer-owned inventory, SKUs, warehouse locations, stock levels, receiving, picking, transfers, and fulfillment — from one centralized cloud-based platform.

Connects inventory with receiving, fulfillment, shipping, customer visibility and billing
Warehouse Inventory · LiveSynced
CustomerSKUQtyLocation
Customer AA-100500A-01-01
Customer AA-200250A-01-02
Customer BA-100300B-02-01
Customer CC-500750C-03-04
Same SKU, different owners — kept fully separate4 accounts shown
Overview

What is 3PL inventory management?

3PL inventory management is the process of tracking and controlling inventory that a third-party logistics provider stores and manages on behalf of its customers. Each customer can have its own products, SKUs, quantities, storage locations, fulfillment rules, and reporting requirements.

A 3PL warehouse may hold inventory belonging to many different businesses inside the same facility. A specialized WMS ensures that every SKU, bin, and pallet remains associated with the correct customer.

Key Questions the System Answers:

  • How much inventory does each customer have?
  • Which SKUs are stored in the warehouse, and where?
  • How much inventory is available vs. allocated to orders?
  • What inventory has been received, shipped, returned, or adjusted?
  • Which customer owns a particular inventory unit?
  • What lot or batch numbers are associated with the stock?
  • Which serial numbers have been shipped to customers?
  • When should replenishment or cycle counts take place?
  • How are storage and handling fees calculated per client?
  • What stock levels should be synced to connected sales channels?
Why it matters

Inventory accuracy is fulfillment accuracy

If the inventory record is incorrect, a warehouse may promise products that aren't available, pick the wrong quantity, or delay an order. For a 3PL, accuracy matters even more — the warehouse manages inventory belonging to multiple businesses at once.

Know what's available

Find inventory quickly and eliminate manual data entry across bins.

Track every movement

Identify and resolve discrepancies before they ever affect an outbound order.

Give customers visibility

Provide client portals with a transparent, reliable record of warehouse activity.

Process orders accurately

Maintain high fulfillment accuracy and client trust across every account.

Core capability

Multi-client inventory management

Multi-client inventory management is one of the fundamental requirements of a 3PL WMS. The same SKU can exist for multiple customers — 3PLSmart keeps every quantity associated with the correct owner.

Inventory by Customer Includes:

  • SKU, product name, and description
  • Available, allocated, on-hand, and reserved quantities
  • Warehouse, zone, aisle, rack, shelf, and bin location
  • Lot number, batch number, and expiration date
  • Serial numbers for serialized units
  • Inventory status (available, damaged, quarantine, hold)
SKU A-100 Across Customers
OwnerSKUQuantity
Customer AA-100500 units
Customer BA-100300 units
Never treated as one shared pool — each client's inventory is strictly isolated.
Products & locations

SKU management and warehouse locations

Accurate product data — and knowing exactly where that product sits — makes receiving, picking, packing, shipping, and reporting reliable.

Product Information

SKU, description, barcode, weight, dimensions, units of measure, and customer ownership.

Lot & Serial Data

Lot information, serial numbers, manufacturing date, and expiration where applicable.

Product Status

Keep real-time product statuses connected to inventory across the entire warehouse flow.

Warehouse AZone 1Rack 03Shelf 02Bin 04
Receiving

Inventory receiving & putaway

Inventory enters the warehouse through receiving operations, then moves into storage — creating a continuous connection between inbound activity and inventory availability.

01

Create or import an inbound shipment

Identify the owning customer and verify expected products, quantities, and ASNs.

02

Record discrepancies and receive

Scan barcodes, capture damaged items, and record verified quantities.

03

Make available for fulfillment

System-directed putaway moves received inventory into designated bin locations.

Inventory states

Available, reserved, and allocated inventory

Understanding these states prevents warehouse teams from assuming all physical inventory is immediately available for new orders.

On-Hand

Physical inventory

Total units physically located inside the warehouse right now.

Available

Ready to fulfill

Units ready and uncommitted for new customer orders.

Reserved

Held inventory

Units set aside for backorders, promotional holds, or quarantine.

Allocated

Assigned to order

Units actively committed to open pick waves and packing tasks.

Movement & fulfillment

From receiving to shipping — fully tracked

A movement history provides operational visibility and helps with inventory investigations, from adjustments and transfers through cycle counts and order allocation.

ReceivingStoragePickingPackingShipping

Adjustments

Record why a discrepancy occurred with an auditable reason code and full history.

Transfers

Move inventory seamlessly between warehouse bins, zones, or secondary facilities.

#

Lot & Batch Tracking

Trace production runs, manufacturing dates, and shelf-life expiration dates.

Serial Tracking

Track individual serialized units for high-value electronics and warranty management.

Accuracy tools

Barcode scanning & cycle counting

Barcodes connect physical inventory to the digital WMS. Cycle counting verifies system inventory matches what's actually on the shelf — without stopping the warehouse.

Barcode Scanning Covers:

Receiving, putaway, picking, packing, inventory counting, and location transfers — eliminating manual entry mistakes at every stage.

Cycle Counts Can Target:

Selected customers, SKUs, locations, or product groups — with authorized adjustments recorded automatically on any variance found.

Visibility

Customer visibility, reporting & billing

3PL customers expect real-time visibility without contacting the warehouse for every question. As a 3PL grows to multiple warehouses, centralized visibility becomes essential.

Inventory Reporting

Movement, adjustments, received, shipped, available, and allocated inventory — by customer, SKU, warehouse, or location.

🜍

Billing Integration

Storage, receiving, handling, pick and pack, transfers, and returns connect directly to customer billing rate cards.

Comparison

3PL inventory management vs. standard inventory software

Standard software tracks stock for a single business. 3PL inventory software manages stock for multiple customers inside the same warehouse.

CapabilityStandard Inventory Software3PL Inventory Management
Inventory tracking
SKU management
Warehouse locations
Multiple customersLimited / variesCore requirement
Customer-owned inventoryLimited / variesCore requirement
Customer portalVariesImportant
Customer-specific billingLimited / variesImportant
Multi-warehouseVariesImportant
EDIVariesImportant for B2B
Customer integrationsVariesCore requirement
How 3PLSmart works

One continuous inventory workflow

01

Receive

Record incoming customer inventory and ASNs.

02

Store

Assign inventory to verified warehouse locations.

03

Track

Monitor stock quantities and movement history.

04

Allocate

Reserve available stock for incoming customer orders.

05

Pick

Guide pickers to exact product and bin locations.

06

Ship

Update inventory levels as orders leave the dock.

07

Report

Provide real-time visibility to operators and clients.

08

Bill

Convert storage and handling activity into charges.

Who it's for

Who needs 3PL inventory management software?

Third-Party Logistics Providers

Manage customer-owned inventory across multiple client accounts from a centralized system.

E-Commerce Fulfillment Companies

Sync stock levels with Shopify, Amazon, and marketplaces while fulfilling DTC orders.

B2B Fulfillment Providers

Support retail routing, palletized storage, lot control, and EDI supply chain documents.

Growing Fulfillment Warehouses

Replace error-prone spreadsheets with structured location barcodes and cycle counts.

Buyer's Guide

What should you look for in 3PL inventory software?

The best system connects inventory directly to warehouse execution and customer billing rather than treating inventory as a standalone spreadsheet.

Multi-client inventory separation
Real-time available vs. allocated stock
Location hierarchy (zone, aisle, bin)
Barcode and QR code scanning
Lot and batch tracking
Serial number tracking
Cycle counting & variance logs
Inter-location and warehouse transfers
Automated inventory adjustments
Customer portal self-service visibility
E-commerce & marketplace stock sync
EDI inventory advice (EDI 846)
Storage rate calculation & billing
Expiration date & shelf-life tracking
Kitting and assembly tracking
Multi-warehouse network support
Audit trail for all stock movements
REST API for external system integrations
FAQ

Frequently asked questions

What is 3PL inventory management?+

3PL inventory management is the process of tracking, storing, moving, and fulfilling inventory on behalf of multiple customers, keeping each customer's inventory associated with the correct products, quantities, locations, orders, and warehouse activity.

How is 3PL inventory management different from regular inventory management?+

Regular inventory software typically manages inventory for a single company. 3PL inventory management must manage inventory for multiple distinct customers within the same warehouse, maintaining strict separation of stock, customer-specific billing rules, and individualized customer portal access.

Can a 3PL WMS manage inventory for multiple customers?+

Yes. Multi-client inventory management is a fundamental requirement of a 3PL WMS. 3PLSmart isolates inventory by customer account across every warehouse, zone, and bin location.

How does a 3PL track inventory?+

A 3PL tracks inventory using barcode scanning, system-directed putaway, real-time location assignments (aisle, rack, shelf, bin), cycle counting, and detailed movement logs from receiving through outbound shipping.

What is multi-client inventory?+

Multi-client inventory refers to storing and managing products owned by different commercial clients inside a shared warehouse facility while keeping records, stock levels, orders, and billing completely segregated per client.

Can two 3PL customers have the same SKU?+

Yes. Two customers can use the same SKU or product identifier. The WMS associates each inventory quantity with the specific customer ID so that their physical stock and reporting are never commingled.

Does a 3PL WMS track inventory locations?+

Yes. A warehouse management system associates inventory with specific warehouse locations such as zones, aisles, racks, shelves, and bins for rapid, accurate picking and replenishment.

Can 3PL inventory software track lot numbers?+

Yes. 3PLSmart supports lot and batch tracking, including manufacturing dates, expiration dates, and lot-specific inventory movement for regulated or perishable goods.

Can a 3PL WMS track serial numbers?+

Yes. The system can capture serial numbers during receiving, storage, order fulfillment, and returns to provide end-to-end traceability for high-value or electronic items.

How does inventory management connect with order fulfillment?+

When an order is received, the WMS checks available inventory for that specific customer, allocates the required units, directs pickers to the exact bin location, and updates available stock immediately upon fulfillment.

Can customers see their inventory in a 3PL WMS?+

Yes. A customer portal provides authorized clients with 24/7 self-service visibility into their real-time stock levels, SKU breakdowns, order statuses, shipments, and billing activity.

Does 3PL inventory management support multiple warehouses?+

Yes. Modern 3PL WMS platforms support multi-facility networks, allowing operators and clients to view stock availability, transfers, and fulfillment routing across all warehouse locations.

Can inventory management connect to e-commerce platforms?+

Yes. 3PLSmart integrates with platforms like Shopify, Amazon, Walmart, and TikTok Shop to sync inventory levels automatically and prevent overselling.

Why is inventory accuracy important for a 3PL?+

Inventory accuracy is fulfillment accuracy. Accurate inventory prevents delayed orders, stockouts, mis-picks, customer disputes, and unexpected billing discrepancies across client accounts.

Get Better Visibility Into Your 3PL Inventory

Your warehouse should always know what inventory you have, who owns it, where it is located, and what is available to fulfill orders.