Beyond the WMS: The Technology a Modern 3PL Needs for Field Inventory
A WMS runs the warehouse. It cannot run the field. Here's the 3PL technology stack that adds field inventory without replacing your WMS, and goes live in 4-8 weeks.
The WMS is not the whole stack
For most 3PLs, third party logistics software means the WMS. It runs the warehouse: receiving, putaway, picking, packing, slotting. Paired with a TMS for transport, it is the backbone of the operation, and it should stay that way.
But the backbone has a gap. The WMS sees inside the four walls. The field, where consigned stock, van inventory and site stock now live, is invisible to it. As 3PLs move into higher-value field services, that gap becomes the limiting factor.
The modern 3PL stack is not a bigger WMS. It is a WMS plus a layer built for everything the WMS cannot see.
Why you cannot stretch the WMS to cover the field
WMS vendors offer mobile and field modules. Most do not survive contact with reality, for architectural reasons:
- The WMS assumes a fixed location, trained operators and connectivity. The field has none of those.
- WMS customisation cycles run months. Field operations need to iterate in weeks.
- WMS field modules typically stall at low adoption and break on the next upgrade.
We make the same architectural case in your ERP doesn't know what's outside the warehouse. Stretching the warehouse system to do field work is the wrong tool for the job.
What to add: the field inventory layer
The missing piece is a field inventory layer that sits alongside the WMS and TMS. When evaluating it, the field capabilities matter more than warehouse features:
- Mobile-first and offline-capable, for vans, sites and dead zones.
- Role-based workflows for reps, nurses and engineers, not logistics analysts.
- Multi-client by design, so one platform serves many customers with clean separation.
- Real-time, per-client visibility the 3PL can expose as a dashboard.
- Two-way integration with the WMS, the TMS and the customer's ERP. See systems integrations.
The WMS stays the system of record inside the warehouse. The field layer extends the stack to everything beyond it.
The proof
Ventory runs field inventory across 450+ locations for enterprise customers in MedTech, 3PL, logistics and consumer goods, with stock accuracy above 99% and field adoption above 95%. A national ambulance service holds 99.76% accuracy across a fleet of 100 vehicles restocked by crews between calls. The platform integrates with SAP, Oracle, Microsoft Dynamics, Sage and NetSuite, so it slots into the stack a 3PL already runs. Deployment runs 4-8 weeks. For the vertical view, see Ventory for 3PL.
Getting started
If your stack stops at the warehouse:
- Map where client stock sits beyond the four walls and which contracts depend on it.
- Score field inventory tools on the field capabilities above, not warehouse features.
- Pilot a field inventory layer alongside your WMS for one client. Target 4-8 weeks.
- Measure visibility, adoption and contract value.
- Scale across the book.
Running a warehouse stack against a field problem? Book a demo →
Frequently asked questions
What is third party logistics software?
Third party logistics software is the technology a 3PL uses to run its operation, centred on the warehouse management system (WMS) for warehouse operations and the transport management system (TMS) for transport. A modern stack also includes a field inventory layer for stock that sits outside the warehouse.
Why can't a WMS handle field inventory?
A WMS is built for fixed, scanner-rich warehouse operations. It assumes a fixed location, trained operators and connectivity, none of which the field offers. Its customisation cycles are too slow for field iteration, and WMS field modules typically stall at low adoption and break on upgrade.
What is a field inventory layer in the 3PL stack?
It is a mobile-first, offline-capable, multi-client platform that tracks stock outside the warehouse and integrates with the WMS, TMS and customer ERP. It extends the stack rather than replacing the WMS, covering consignment, van stock and site inventory.
Do I have to replace my WMS?
No. The WMS stays the system of record inside the warehouse. The field inventory layer adds the capabilities it lacks and syncs both ways, so you get one source of truth from the warehouse to the field.
How long does it take to deploy?
Typically 4-8 weeks for a pilot with one client and 3-6 months to scale, integrating with the WMS, TMS and ERP you already run.
About Ventory
Ventory is the field inventory layer for regulated, high-stakes industries. We give MedTech, 3PL, Aerospace, Energy and FMCG leaders real-time visibility and control over inventory outside the four walls, in hospitals, ambulances, trunk stock, consignment locations, and field service vans. Ventory is ERP-agnostic (SAP, Oracle, Dynamics, Sage, NetSuite) and trusted by a global medtech manufacturer, a national ambulance service, and global logistics and consumer-goods operators. See how it works →