Project Overview
A UK B2B procurement marketplace connecting 340 UK manufacturers with 2,800 business buyers needed to rebuild ...
Technology Stack
Compliance & Standards
The Challenge
A UK B2B procurement marketplace connecting 340 UK manufacturers with 2,800 business buyers needed to rebuild their platform from a legacy PHP monolith. The marketplace handled £28M GMV (Gross Merchandise Value) per year, but the monolith could not support: real-time inventory sync with manufacturer ERPs, buyer workflow approvals (purchase order authorisation chains), punch-out catalogue integration (eProcurement standards), or the API access that enterprise buyers needed for ERP integration. Budget: £180,000.
Our Approach
First Architecture
- OpenAPI 3.0 specification designed first — before any implementation.
- All marketplace functionality available via REST API (product search, order placement, inventory check, invoice retrieval).
- Versioned endpoints (/v1/).
- Buyer SDK published on GitHub (TypeScript).
- Enterprise buyers integrate directly from their ERP (SAP, Oracle, Dynamics 365) using the API.
Manufacturer inventory sync
webhooks from manufacturer ERPs (push model) to the marketplace inventory service. 12 manufacturer
ERP systems supported
- SAP Business One, Sage 50, Xero (via inventory add-on), and bespoke systems via CSV upload.
- Real-time inventory prevents overselling — common pain point on the legacy system.
- Punch-Out Catalogue (cXML/OCI): Enterprise buyers use eProcurement systems (Ariba, Coupa, Oracle iProcurement) that require punch-out catalogue integration. cXML and OCI (Open Catalogue Interface) standards implemented.
- Buyer initiates punch-out from their eProcurement system → browses marketplace product catalogue → returns selected items to their requisition → generates purchase order via marketplace API.
Purchase Order Approval Workflows
- UK enterprise buyers need PO approval chains (e.g., orders over £5,000 require line manager approval
- over £20,000 require finance director).
- Configurable approval workflows per buyer organisation.
- Email approval via GOV.UK Notify-style notification (with one-click approve/reject).
- Approval audit trail for finance team.
The Results
Launched at 22 weeks, £174,000 — under budget.
API adoption: 28 enterprise buyers connected their ERP within 6 months.
Punch-out: 8 major buyers using eProcurement integration.
GMV growth: £28M → £41M in 12 months (47% increase — API access unlocked enterprise procurement budgets).
Manufacturer inventory accuracy: 99.2% (previously 87% — overselling eliminated).
Customer support contacts per £1M GMV: down 65%.
“The punch-out integration opened up procurement budgets that were completely inaccessible to us before. Enterprise procurement systems literally cannot place orders without punch-out. The API-first approach — building the spec before writing a line of code — meant our enterprise buyers could start integration planning while we were still building." — CEO, UK B2B Marketplace (name withheld)”
Project Details
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