The verdict in three sentences
For a group with 1,200 employees processing 5,000 purchase requests a year, a custom approval platform costs between 60,000 and 140,000 SGD and overtakes an off-the-shelf suite on total cost by the third year. The real gain is not the software itself but the approval lead time, which can drop from 9 days to under 3 with a three-level workflow and automatic reminders. The choice between custom and SaaS comes down to two measurable criteria: the number of active users and the depth of ERP integration.
What email approvals really cost
A procurement head running approvals by email pays a hidden cost that is rarely measured. Each request passes through 4 to 6 inboxes on average, chasing approvals takes 15 to 25 minutes per file on the buyer side, and part of the spend is committed before approval (maverick buying). Across 5,000 requests, the bill adds up.
| Annual cost item (2026 estimate) | Email approvals | Approval platform |
|---|---|---|
| Average approval lead time | 9 days | 2 to 3 days |
| Buyer time per request (chasing, ERP entry) | 35 min | 10 min |
| Buyer hours across 5,000 requests | 2,920 h | 830 h |
| Cost of those hours (70 SGD loaded per hour) | 204,400 SGD | 58,100 SGD |
| Estimated off-process spend | 8 to 12% of volume | 1 to 3% |
| Audit and internal control traceability | Weak, scattered | Complete, timestamped |
The gap of roughly 146,000 SGD in buyer time per year is an estimate to recompute with your own volumes. It still shows that a platform budget should not be compared with zero, but with the current cost of the process.
Custom build or market suite: 5-year total cost
Procure-to-pay suites are priced in 2026 between 12 and 22 SGD per user per month, with setup fees often between 15,000 and 40,000 SGD for configuration and the ERP connector. A custom application requires a higher upfront investment, then recurring costs limited to maintenance and hosting.
| 5-year item (400 active users) | Market SaaS suite | Custom application |
|---|---|---|
| Setup and ERP integration | 15,000 to 40,000 SGD | Included in the project |
| Initial development | 0 | 60,000 to 140,000 SGD |
| Licences (18 SGD x 400 x 60 months) | 432,000 SGD | 0 |
| Evolutive maintenance (15% of build per year) | Included | 45,000 to 105,000 SGD |
| Hosting and monitoring | Included | 15,000 to 25,000 SGD |
| 5-year total (estimate) | 447,000 to 472,000 SGD | 120,000 to 270,000 SGD |
The break-even point depends on user count. Below 80 to 100 active users, a market suite is often cheaper. Above 250, custom wins, especially if your approval workflow has specific rules (thresholds by spend category, cost centres, delegation during leave).
Typical scope of a 3 to 5 month project
A well-scoped project is split into deliverable lots, so the core workflow goes live before the advanced integrations.
| Lot | Content | Indicative duration | Share of budget |
|---|---|---|---|
| Scoping | Procurement, finance and IT workshops, threshold matrix | 2 to 3 weeks | 8 to 10% |
| Approval workflow | Form, 3 levels (manager, budget, procurement), delegations | 5 to 7 weeks | 30 to 35% |
| ERP integration | Suppliers, cost centres, purchase order creation | 4 to 6 weeks | 25 to 30% |
| Dashboards | Lead time per level, spend per department, alerts | 2 to 3 weeks | 10 to 12% |
| SSO and security | Microsoft Entra ID or Google sign-in, audit logs | 1 to 2 weeks | 5 to 8% |
| Testing and rollout | Tests, approver training, migration of open requests | 2 to 3 weeks | 10 to 12% |
A three-level workflow covers most needs of a mid-sized group: line manager approval, budget control by finance, then a procurement sign-off above a threshold (often 10,000 or 20,000 SGD). ERP integration is the riskiest lot: secure access to a test environment during scoping.
Mini case study
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Wei Ling, head of procurement at a 1,200-employee distribution group in Singapore, has 400 active requesters and approvers. Working assumption: a custom application at 95,000 SGD, plus 14,250 SGD a year of maintenance and 4,000 SGD a year of hosting, giving 186,250 SGD over 5 years. The best-placed market suite costs 18 SGD per user per month plus 30,000 SGD of setup, giving 462,000 SGD over 5 years.
The 275,750 SGD gap comes on top of the buyer time saved, estimated at 2,090 hours a year. Even counting only half of that gain, the project pays back in under 12 months. Wei Ling therefore brings her board a business case built on total cost, not on the entry price alone.
FAQ
How long does it take to roll out a purchase request platform?
Allow 3 to 5 months for a mid-sized group, including 2 to 3 weeks of scoping. The approval workflow can go live in month three, with full ERP integration following.
Can the application connect to SAP, Oracle NetSuite or Microsoft Dynamics?
Yes, through APIs or scheduled file exchange. The connector usually represents 25 to 30% of the budget, around 15,000 to 42,000 SGD depending on the quality of the available APIs.
How many approval levels should we plan for?
Three levels are enough in most groups: manager, budget control and procurement above a threshold. Beyond 4 levels, the average lead time climbs quickly, often above 5 days.
Who owns the code of a custom application?
The contract should assign the intellectual property and hand over the source code at delivery. This is a clear advantage over a SaaS suite you rent every month.
What annual budget should we plan after go-live?
Plan 12 to 18% of the development cost per year for corrective and evolutive maintenance, which is 7,200 to 25,200 SGD for a 60,000 to 140,000 SGD project, plus hosting.
Let's scope your project. Send us your request volume, your ERP and your approval thresholds: we will price the scope, an indicative budget and a phased schedule. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
