Your London 3PL runs a dozen brands' stock through a WMS that thinks it has one client
Custom WMS development in London typically runs £70k to £200k over 5 to 9 months. You build custom when one warehouse serves many clients with different rules, when an ERP (Enterprise Resource Planning) add-on or single-tenant Manhattan deployment can't model the multi-brand, multi-SLA reality of a London 3PL. The trigger is usually the day a picking error or a billing dispute between two clients exposes that the system can't really tell them apart.
Manhattan and ERP warehouse add-ons assume one company's stock, one set of rules, one way of picking and packing. A London 3PL or shared-fulfilment operation lives in the opposite world: a dozen DTC brands under one roof, each with its own SKUs, packaging requirements, SLAs, returns policy, and billing model. The off-the-shelf WMS treats it as one big warehouse, so the per-client logic that is the actual business gets bolted on in spreadsheets and standard operating procedures taped to shelves.
That mismatch creates real problems. Picking errors happen because the system can't enforce brand-specific packing rules. Client billing is disputed because the WMS can't accurately attribute storage and handling per brand. SLAs are managed manually, so a missed cutoff for one client surfaces too late. The WMS that should be the operating system of a multi-client warehouse instead pretends every client is the same, which is the one thing a 3PL can never afford to do.
Where the off-the-shelf tools fall short
- An ERP add-on or Manhattan treats a multi-brand 3PL as one warehouse with one rulebook
- Brand-specific packing and SLA rules live in SOPs and spreadsheets, not the system
- Per-client storage and handling can't be attributed accurately, so billing is disputed
- Picking errors happen because the system can't enforce each brand's requirements
Custom warehouse management: what London teams actually get
A London 3PL is a multi-client business, and its WMS needs to be multi-tenant by design, with each brand's SKUs, packing rules, SLAs, and billing modelled as first-class. Custom WMS development builds that in: brand-specific picking and packing enforced on the floor, per-client billing attributed accurately, and SLA tracking that warns before a cutoff is missed. The system finally treats your clients as the distinct businesses they are, which removes the picking errors, billing disputes, and SLA misses that one-size-fits-all WMS causes.
- One warehouse serves multiple brands with genuinely different rules and billing
- Brand-specific packing and SLAs are managed in spreadsheets and taped SOPs
- Per-client billing is disputed because the system can't attribute costs
- Picking errors trace back to the system not enforcing each brand's requirements
- You run a single-client or single-brand warehouse with uniform rules
- An ERP warehouse add-on covers your fulfilment without workarounds
- Per-client billing and SLA differentiation aren't part of your model
- Volume and client count don't justify a multi-tenant custom build
- True multi-client model: each brand's SKUs, rules, and billing as first-class data
- Brand-specific packing enforced on the floor, cutting picking and fulfilment errors
- Accurate per-client storage and handling attribution, ending billing disputes
- SLA tracking that warns before a client's cutoff is missed
- One system that runs the multi-brand warehouse instead of spreadsheets and taped SOPs
- Multi-tenant warehouse logic is complex and drives cost and timeline
- Hardware integration (scanners, label printers, conveyors) adds real engineering risk
- You own uptime for a system the warehouse can't operate without
- A single-client warehouse genuinely doesn't need this; an ERP add-on suffices
Feature priorities for London teams
What we build under warehouse management in London
Digital Heroes builds the full warehouse management stack for London teams. Typical engagements cover barcode and RFID, slotting optimization, inbound and outbound logistics, fulfillment software, 3PL software and warehouse management system (WMS).
The honest cost picture for London
| Project scope | Typical cost | Timeline |
|---|---|---|
| Custom multi-tenant WMS for a London 3PL | £90k to £160k | 6 to 8 months |
| Full WMS with floor automation and carrier integration | £140k to £200k | 7 to 9 months |
| Per-client billing and SLA module over existing WMS | £60k to £100k | 4 to 5 months |
Timeline: what happens, and when
Exactly what you get
A warehouse system built for what a London 3PL actually is: many brands under one roof, each distinct. Per-brand SKUs, packing rules, SLAs, and billing modelled as first-class data. Directed picking and packing that enforces each client's requirements on the floor, cutting errors. Accurate per-client cost attribution that ends billing disputes. And SLA tracking that warns before a cutoff is missed. The spreadsheets and taped SOPs that currently hold the per-client logic move into one system that runs the whole operation.
How to choose a developer in London
Hire a team that has built multi-tenant warehouse systems and integrated real floor hardware, because per-client logic and scanner-driven workflows are where this work succeeds or fails. Ask how they'd enforce one brand's packing rules versus another's on the floor, and how they'd attribute storage costs per client for billing. A partner modelling a single client has misunderstood the business. Connect the WMS to your inventory management software, supply chain software, and ERP so stock, fulfilment, and client billing share one source of truth.
- !They model one client; ask how they handle per-brand rules and billing
- !No floor-hardware experience; ask which scanners and printers they've integrated
- !Per-client billing is hand-waved; ask how they attribute storage and handling
- !SLA tracking is missing; ask how they warn before a client's cutoff is missed
- !Quote without walking the warehouse; ask for a floor-operations audit
If warehouse management is on the roadmap, business intelligence dashboards, lms, internal tools usually follow within the year. Budget them as one conversation.
Rohan advises mid-market and enterprise teams on ERP, CRM and custom software, and has led delivery on dozens of business-software builds.
Writes for Digital Heroes, shipping business software for 2,000+ brands across 55+ countries since 2017.
Frequently asked questions
Why can't an ERP warehouse add-on run our 3PL?
ERP add-ons assume one company's stock and one rulebook. A 3PL runs many brands with different SKUs, packing rules, SLAs, and billing, so the per-client logic that is the actual business gets pushed into spreadsheets. A custom multi-tenant WMS models each client as a first-class entity.
How does the WMS reduce picking errors?
By enforcing each brand's specific picking and packing rules on the floor through directed workflows on the scanner, rather than relying on staff to remember which client needs what. The system won't let a brand's order be packed against another brand's rules.
Can it bill clients accurately?
Yes, and that's often the strongest case. The custom WMS attributes storage, handling, and value-added services per client based on actual activity, ending the billing disputes that arise when a single-tenant system can't tell clients' costs apart.
Do we need to replace our whole WMS?
Not always. A per-client billing and SLA module can sit over an existing WMS to add the multi-tenant attribution it lacks. A full custom WMS makes sense when the base system can't enforce per-brand floor rules either.