Purchase orders chased through email, a spreadsheet someone always breaks, invoices that don’t quite match what was ordered, and off-the-shelf software that almost fits but not quite. If any of this sounds familiar, you’re in the company of most UK SMEs we talk to. Generic PO systems tend to ask you to reshape your procurement around the software, which is backwards.
The pain usually starts at a predictable point. You add a second site or a third department. An audit flags weak purchasing controls. Someone overspends a budget and nobody catches it until month-end. Your finance team is re-keying purchase data into the accounts by hand. That’s the moment a proper system stops being optional.
We build custom purchase order software for the way your business actually runs. The result is a system you own outright, that fits your approval chain, talks to your existing accounting package, and doesn’t bill you per user every month for the privilege.
We’re a London-based automation consultancy, and most of our work is with UK SMEs. That means we tend to know what HMRC expects on retention and audit trails, what your accountant uses, and the kind of approval chain that makes sense for a 30-person business versus a 300-person one.
To be clear: SaaS is often the right answer
We won’t pitch you a custom build you don’t need. If your approval chain is one to three simple levels, you run a single cloud accounting package, your supplier list is manageable, and you have no legacy systems to connect, a tool like Precoro, Procurify or one of the SME-focused platforms will do the job and go live in a month or two. That’s a sensible choice, and we’ll say so.
Custom earns its keep when the off-the-shelf options stop fitting. Usually that means complex conditional approvals, a legacy or in-house ERP nobody makes a connector for, multiple legal entities, very high PO volume, or per-user pricing that has quietly become a tax on growth. The rest of this page is about that situation.
Where off-the-shelf PO software falls short
Generic systems tend to cause the same problems over and over:
- Approval workflows are rigid. They cope with “over £10k goes to the FD” but not “IT spend over £25k needs the CTO and procurement” or an emergency order that has to be approved retroactively. Teams hit the limit and quietly go back to email.
- The per-user monthly fee looks small until you add up five years of it, plus the 3 to 15 percent annual increases most contracts allow. Some clients end up locking people out of the system to keep the licence count down.
- Accounting integration is rarely as clean as the demo. Sync delays, vendor codes and cost centres that don’t map, goods receipts that still need re-keying into the accounts, and supplier master data that drifts out of sync between the two systems.
- Enterprise platforms solve the flexibility problem but bring six to twelve month implementations and heavy consulting fees, which is overkill for most SMEs.
- Industry quirks (NHS framework rules, CDM compliance, charity donor restrictions, batch traceability) usually don’t fit a standard template.
- Reporting is whatever the vendor decided. A genuinely custom report often means a professional-services ticket.
What we usually see is teams building workarounds on top of the software they’re paying for. Side spreadsheets, manual re-entry, reconciliation headaches at month-end. The licence fee is rarely the biggest cost.
How we approach it differently
We build around your procurement workflow rather than asking you to bend to ours. A few things that tend to matter to clients:
Process-focused design. We spend the first couple of weeks mapping how POs actually move through your business, including the bits no one wrote down, who can approve what, and where things currently get stuck. Then we build to that.
You own it. You pay for the build and the software is yours, including the data and the source code. Optional support is there if you want it, but you’re not on a subscription treadmill, and there are no exit fees if you decide to take it in-house.
Integration done properly. Xero, QuickBooks, Sage, NetSuite, Dynamics, your ERP, your warehouse system. We connect through proper APIs and we deal with the unglamorous parts: GL and cost-centre mapping, keeping the supplier master in step, and making sure receipts flow through without re-keying.
UK-specific by default. VAT and reverse charge handled correctly, audit trails that satisfy HMRC’s six-year retention rules, CIS for construction clients. Built in, not bolted on.
Room to grow. Add users at no extra cost, add features, add a whole new module two years from now. The architecture is built to be extended rather than frozen in a quarterly release cycle.
Local support. Our team is in London. If something needs a conversation, you get one during UK business hours, not a ticket queue in another time zone.
Features we typically build in
Every project is shaped to the client, but these are the core capabilities most systems include:
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PO creation from scratch or from requisitions, with line items, units of measure, GL coding and your business rules baked in.
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Multi-level approval workflows with conditional routing by amount, category, cost centre, vendor and requester role, plus parallel approvals and escalation when an approver sits on something for too long.
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Budget tracking that separates committed spend (POs raised but not yet invoiced) from actual spend, with real-time remaining balances and the option to block or flag orders that would push a department over.
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Three-way matching of PO, goods receipt and supplier invoice, with your variance tolerances and automatic holds on anything that doesn’t reconcile.
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A supplier master with payment terms, tax and VAT details, performance metrics, certifications and insurance expiry, plus an optional portal so suppliers can see order and invoice status without phoning your team.
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Goods receipt against POs, including partial deliveries, batch and serial numbers, and damaged-goods handling.
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Mobile approvals, so approvers aren’t stuck at a desk to sign off on a £400 order.
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Reporting and dashboards you can actually configure: spend by vendor or category, budget versus actual, supplier scorecards, approval bottlenecks and compliance exceptions, with a feed into Power BI if you use it.
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An immutable audit trail for every PO, change, approval, receipt and invoice match, with segregation of duties so the same person can’t requisition, approve, receive and invoice.
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Role-based access, encryption, backups and UK GDPR-compliant data handling as standard.
How a typical project runs
We work in four phases, and most builds land in the three-to-six month range.
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Discovery and planning (2-4 weeks). Interviews with finance, procurement and the people who actually raise POs, a process map of how procurement really works, your approval matrix and spending limits, and a written spec we both sign off before any code is written.
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Development (6-16 weeks). Our UK developers build the system in modern frameworks. We start with a usable core (create PO, approve, track, one accounting integration) and add three-way matching, reporting, the supplier portal and other modules in phases, so you’re not waiting for everything before you see anything.
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Testing and deployment (2-4 weeks). The unglamorous but important part: cleaning and migrating supplier master data, deduplicating vendors, mapping GL codes and cost centres, importing historical POs where it helps the audit trail, validating integrations, and user acceptance testing. Rollouts are phased, often with a pilot team and a short parallel run rather than a big-bang switchover.
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Training and support (ongoing). Hands-on sessions and documentation for each role, from approvers who need 30 minutes to admins who need half a day, plus an optional support agreement if you want one.
A focused first version can be live in 6 to 12 weeks. Builds with several integrations or multi-entity consolidation take closer to six months, and regulated or legacy-ERP work can run longer. Underestimating data migration is the most common reason PO projects slip, so we plan it properly from day one rather than treating it as an afterthought.
What it costs
A custom build costs more upfront than a SaaS subscription. Over a few years the comparison tends to even out, and for a growing team it often tips the other way.
The sticker price on SaaS is rarely the real cost. Mid-market PO platforms typically run somewhere around £40 to £80 per user per month, so 20 users is roughly £10,000 to £20,000 a year. On top of that sit setup and onboarding fees, data migration, paid integration work, premium support tiers, and annual increases that contracts commonly allow at 3 to 15 percent. Per-user pricing also penalises growth: every new hire who needs access adds to the bill.
A custom build is a larger one-off investment. After it’s delivered you only pay for the support you choose to keep, the cost doesn’t climb every renewal, and adding users is free. You own the software and the data, so there’s no lock-in and no exit fee if you ever want to move on.
Costs depend heavily on scope, and we’d rather give you a real number after discovery than a figure pulled from thin air. As a rough guide: a focused first version covering core PO management, approvals, budget tracking and one accounting integration is the smaller end of the range; multi-integration builds with three-way matching, a supplier portal and reporting sit in the middle; regulated-industry or multi-entity work with legacy ERP integration is the larger end. We’ll be straight with you about where your project lands before you commit.
Where custom PO systems tend to earn their keep
Custom work makes the most sense where the off-the-shelf options don’t quite fit. The awkward, sector-specific detail is usually where the real value sits:
- Manufacturing, where POs need to line up with production schedules and supplier lead times, often generated off reorder points or an MRP run, with batch and serial tracking for traceability.
- Construction, with subcontractor and materials orders tied to project budgets and cost centres, supplier prequalification for safety certificates and insurance, change-order handling, and CDM compliance.
- Healthcare, including NHS framework and contract terms, supplier credential checks, and segregation of duties for high-value and controlled items.
- Food and beverage, where ingredient orders need supplier audit and certification tracking, allergen checks, and batch and shelf-life records for HACCP traceability.
- Pharmaceutical and other regulated manufacturing, with GMP supplier qualification, certificate-of-analysis review against specification, and an immutable audit trail.
- Retail and e-commerce, where POs sync with multi-warehouse inventory and demand forecasts to avoid stockouts and overstock.
- Professional services, tracking client-billable purchases against project budgets.
- Charities and non-profits, where donor-restricted funds need watertight approval rules and clean reporting.
- Multi-entity groups, often after an acquisition, that need separate spend tracking and GL accounts per entity while consolidating payables and reporting at group level.
Generic software handles the easy 80%. We’re usually hired for the other 20%, and that’s the part that actually moves the numbers.
Common Questions About Custom Purchase Order Management Software
How does a custom build compare on cost to PO SaaS?
Per-user SaaS looks cheap at first and adds up. A mid-market platform at around £40 to £80 per user per month for 20 users is roughly £10,000 to £20,000 a year, before setup, data migration and integration fees, and before the 3 to 15 percent annual increases most contracts allow. A custom build is a larger one-off cost, after which you only pay for the support you choose. For most clients the maths favours ownership over a few years, especially if user numbers are growing. We give you a real figure after discovery rather than a number from thin air.
When is off-the-shelf PO software the better choice?
Be honest with yourself. If you have simple one to three level approvals, a single cloud accounting package, a manageable supplier list and no legacy systems to connect, a SaaS tool will likely do the job and go live fast. Custom makes sense when your approval logic is genuinely complex, you need to connect a legacy or in-house ERP, you operate across multiple entities or currencies, or per-user pricing is becoming a tax on growth. We will tell you which camp you are in.
What's the typical development timeline?
A focused first version covering PO creation, approvals, budget tracking and one accounting integration usually takes 6 to 12 weeks. Builds with several integrations, three-way matching, a supplier portal or multi-entity consolidation run 3 to 6 months, and a regulated or legacy-ERP project can take longer. We phase the work so you get something usable early rather than waiting for everything.
Can you integrate with our accounting and ERP systems?
Yes. Xero and QuickBooks are the most common for UK SMEs, and we also connect to Sage, NetSuite, Microsoft Dynamics and on-premise or in-house ERP systems. We handle the parts SaaS connectors usually get wrong: GL and cost-centre field mapping, keeping supplier master data in sync, and making sure goods receipts do not need re-keying into your accounts.
How do you handle three-way matching and budget control?
We match the purchase order, goods receipt and supplier invoice automatically, with the variance tolerances you set, and hold anything that does not reconcile. Budgets track committed spend (POs raised but not yet invoiced) separately from actual spend, so a department's remaining balance is accurate, and the system can block or flag orders that would push it over.
What about audit trails, compliance and security?
Every PO, approval, change, receipt and invoice match is logged in an audit trail that cannot be edited after the fact, which is what HMRC and your auditors expect. We build in segregation of duties so the same person cannot requisition, approve, receive and invoice, role-based access, encryption and UK GDPR-compliant data handling. Where a sector needs more, such as supplier certification tracking or batch traceability, we build that in too.
How do you handle updates, training and support?
Training is included, with hands-on sessions and documentation pitched at each role rather than one generic course. You own the software, so you can maintain it in-house if you prefer. Most clients take an optional support agreement for changes and enhancements, handled by our UK team during UK business hours.