The verdict in three sentences
Linking a custom HR app to payroll/HRIS software costs between 7,000 and 20,000 EUR in 2026, depending on whether you sync via API or via payroll-variable export. The API guarantees reliable, traceable flows but needs a certified connector; file export stays 40% cheaper but assumes a human check before import. The major, often underestimated constraint is GDPR compliance on sensitive data (salaries, IBANs, health).
API vs payroll file export: the real trade-off
An HR director who wants approved leave and expenses sent automatically to payroll must choose between full automation (API) and a controlled export. Here are 2026 ranges for Dublin.
| Approach | Initial cost (EUR) | Timeline | Reliability | Maintenance/yr |
|---|---|---|---|---|
| Payroll-variable file export | 7,000 - 11,000 | 4-6 wks | Medium (human check) | 1,500 - 3,000 |
| HRIS API (Sage, BrightPay, Cegid) | 12,000 - 20,000 | 6-10 wks | High | 3,000 - 6,000 |
| Hybrid (API read + export write) | 10,000 - 15,000 | 5-8 wks | Good | 2,500 - 4,500 |
Many payroll vendors now expose APIs, but access and certification terms vary. File export remains a safety net appreciated by cautious payroll teams.
GDPR and HR data: the mandatory line items
Payroll data is among the most sensitive. A serious HR integration carries compliance requirements that can be costed at quote stage.
| GDPR requirement | 2026 detail | Budget impact |
|---|---|---|
| Flow encryption | TLS + encryption at rest | 1,000 - 2,500 EUR |
| Data minimization | Only useful payroll fields | 1-2 days of scoping |
| Access logging | Audit trails | 1,500 - 3,000 EUR |
| Retention period | Automatic purge | 1 day of config |
| Records & DPIA | Impact assessment | 1,500 - 3,500 EUR |
| Fine-grained roles | Per HR role | 1-3 days of dev |
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Mini case study
Niamh, HR Director of a logistics SME in Dublin (140 staff) manually keyed leave and expenses into payroll every month. We scoped an API integration at 16,000 EUR, 8-week timeline, GDPR compliance included. Gain: 2 days/month of data entry saved for payroll, i.e. 24 days/yr x 320 EUR = 7,680 EUR/yr, plus the end of transcription errors on payslips. Payback in 25 months with maintenance, and above all a sharply reduced payroll-dispute risk.
FAQ
API or file export: which to favor? The API if you want zero re-keying and full traceability; export if your payroll team demands a human check before each import. Export costs about 40% less.
Does HR data impose specific constraints? Yes, it is sensitive under GDPR. You need encryption, minimization, access logging and sometimes an impact assessment (DPIA). Budget 3,000 to 8,000 EUR of compliance depending on scope.
Do all payroll tools have an API? No. Sage, BrightPay and Cegid offer them, but some older tools only support file imports. That shapes the architecture and timeline.
What is a realistic timeline? Between 5 and 10 weeks depending on approach: scoping the payroll variables, development, testing on a real pay cycle and compliance acceptance.
What does maintenance cover? From 1,500 to 6,000 EUR/yr: adapting to legal changes (rates, contributions), payroll-API updates and mapping adjustments.
Let's scope your project. Tell us your payroll software, the flows to automate (leave, expenses, variables) and headcount: we quote a GDPR-compliant integration, from 7,000 to 20,000 EUR. 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.
