The verdict in three sentences
For a 900-employee company in Dublin, an expense management SaaS costs EUR 6 to 12 per user per month, while a custom app runs between EUR 70,000 and 140,000 excl. VAT in 2026. With 300 active users, custom does not break even within five years; if the tool is rolled out to all 900 staff, it pays back in about 15 months. The choice depends less on technology than on user count, your expense rules and your ability to own compliant record-keeping.
What a custom expense management app costs
A CFO expects an internal app to match a good SaaS: snap a receipt, automatic reading, two-click approval, clean accounting export. The extra cost comes from company-specific rules: site allowances, per-entity limits, client rebilling. Typical breakdown, as a 2026 order of magnitude.
| Module | 2026 range (EUR excl. VAT) | Content |
|---|---|---|
| Scoping, expense policy, rates | 5,000 to 10,000 | Categories, limits, Revenue civil service rates |
| Mobile app, receipt capture and OCR | 17,000 to 36,000 | Photo, extraction of amount, VAT, date, supplier |
| Multi-level approval workflow | 11,000 to 23,000 | Manager, finance control, over-limit alerts |
| Mileage and subsistence allowances | 6,000 to 11,000 | Revenue-approved mileage bands, overnight rates |
| Compliant digital archiving | 8,000 to 18,000 | Faithful copies, timestamps, secure vault |
| Accounting, payroll and corporate card integration | 14,000 to 29,000 | Sage, Xero, NetSuite, card statement matching |
| Security, SSO, testing | 9,000 to 13,000 | Microsoft 365 sign-in, audit log |
| Total custom | 70,000 to 140,000 | Delivered in 4 to 6 months |
Plan 15% a year for maintenance, or EUR 10,500 to 21,000, to keep up with allowance rates, mobile operating systems and regulation.
SaaS or custom: the numbers
The decisive factor is the number of billed users. In a 900-employee company, roughly a third actually submits expenses: sales staff, field technicians, managers. The math changes if leadership wants the tool open to everyone.
| Criterion | Custom app | SaaS (N2F, Expensya and peers) |
|---|---|---|
| Initial cost | EUR 70,000 to 140,000 | EUR 3,000 to 10,000 for roll-out |
| Annual cost, 300 users | EUR 10,500 to 21,000 (maintenance) | EUR 21,600 to 43,200 (EUR 6 to 12 a month) |
| Annual cost, 900 users | EUR 10,500 to 21,000, unchanged | EUR 64,800 to 129,600 |
| Five-year total, 300 users, mid-range | about EUR 183,750 | about EUR 168,500 |
| Break-even, 300 users | about 6 years | not applicable |
| Compliant archiving | To build and have validated | Usually included and certified |
| Regulatory updates | Your responsibility | Included in the subscription |
SaaS keeps a clear edge on compliance: the vendor absorbs changes, including the move to e-invoicing. Ireland is preparing mandatory B2B e-invoicing under the EU VAT in the Digital Age package, so hotel and travel invoices will increasingly arrive in structured formats.
Three watch-outs with custom
- Compliant archiving. To discard paper originals, Revenue requires electronic records to be complete, legible and retained for 6 years, with integrity guaranteed. Without that, you keep the boxes.
- OCR quality. A receipt-reading service costs EUR 0.02 to 0.10 per receipt. On 7,200 claims a year the line stays small, but recognition must exceed 90% for users to adopt it.
- Team dependency. An internal app must be documented and maintained by a contractually committed provider, or it ages within three years.
Mini case study
Aoife, CFO of a 900-employee engineering firm in Dublin, processes 7,200 expense claims a year for 300 users. Entry and checks take 12 minutes per claim today, or 1,440 hours. With any app, that drops to 3 minutes: 1,080 hours saved, or EUR 48,600 a year at EUR 45 loaded.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Then comes the tool choice. SaaS at EUR 9 a month costs EUR 32,400 a year. Custom costs EUR 105,000 plus EUR 15,750 of annual maintenance. Annual difference: EUR 16,650, so a break-even of about 6 years. Leadership plans to open the tool to all 900 staff for site allowances: SaaS would then cost EUR 97,200 a year, and custom would pay back in about 15 months. Aoife commissions a scoping phase to test that assumption before signing.
FAQ
How long does it take to roll out a custom expense app?
Allow 4 to 6 months, including 3 weeks of scoping. A SaaS goes live in 4 to 8 weeks, accounting integration included.
Can we discard paper receipts with an internal app?
Yes, if digitisation meets Revenue's requirements: complete and legible records, integrity, 6-year retention. Budget EUR 8,000 to 18,000 for this module and have it validated by your auditors.
What does automatic receipt reading cost?
Between EUR 0.02 and 0.10 per receipt depending on the service. For 7,200 claims a year, the budget stays under EUR 750.
Does custom integrate better with accounting?
It fits your chart of accounts, cost centres and client rebilling exactly. SaaS tools offer standard Sage, Xero and NetSuite exports, which are enough in 80% of cases.
From how many users does custom make sense?
As an order of magnitude, beyond 500 to 600 active users, or earlier if your expense rules fall outside standard templates. Below that, SaaS remains the safer choice.
Let's scope your project. Tell us your user count, expense rules and accounting software: we will compare SaaS and custom, with an indicative budget and a 4 to 6 month plan. 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.
