The verdict in three sentences
For an accounting firm in Dublin with 20 to 60 staff, a custom document collection and production tracking tool costs between EUR 30,000 and 80,000 excluding VAT, depending on the number of integrations and the level of automation. The return is measured in time: 2 to 4 hours saved per client file per year, or 1,500 to 3,000 hours across a portfolio of 750 files. With EU e-invoicing (ViDA) rolling out and Ireland moving towards mandatory B2B e-invoicing from November 2028, now is the right moment to take control of the data flow between your clients and your practice software.
What the tool covers and what it costs
The typical partner's need fits in one sentence: stop chasing clients by email for bank statements, invoices and receipts, and know at any time where every file stands. Custom development makes sense when off-the-shelf tools impose a generic client portal, poorly linked to your production software, or when you want a dashboard per staff member that the vendor does not offer.
| Module | Function | 2026 budget (EUR excl. VAT) | Timeline |
|---|---|---|---|
| Client document portal | Mobile upload, OCR, automatic reminders | 8,000 to 18,000 | 3 to 5 weeks |
| Production tracking per file | Statuses, tax deadlines, workload per staff member | 7,000 to 15,000 | 3 to 4 weeks |
| Connector to practice software (CCH, Sage, Xero) | File, ledger and document sync | 6,000 to 20,000 | 2 to 6 weeks |
| E-invoice reception via Peppol access point | Ingest UBL and structured formats | 4,000 to 12,000 | 2 to 4 weeks |
| Engagement letters and signature | Generation, e-signature, reminders | 3,000 to 8,000 | 1 to 3 weeks |
| Certified EU hosting (ISO 27001) | Infrastructure, backups, monitoring | 150 to 600 per month | 1 week |
A baseline project (portal + tracking + one connector) starts at around EUR 30,000 excl. VAT. A full project with two connectors, e-invoice reception and a partner dashboard reaches EUR 65,000 to 80,000 excl. VAT. Budget 15 to 20% of the initial cost per year for ongoing maintenance.
Custom tool or vendor portal: the numbers side by side
Vendors offer collaborative portals as standard or as an add-on. They are often enough for a 10-person firm. Beyond 20 staff, the limits show: rigid workflows, weak reporting, a per-file cost that keeps climbing.
| Criterion | Vendor portal (SaaS) | Custom tool |
|---|---|---|
| Entry cost | EUR 0 to 5,000 | EUR 30,000 to 80,000 excl. VAT |
| Recurring cost for 750 files | EUR 3 to 8 per file per month, i.e. EUR 27,000 to 72,000 per year | EUR 5,000 to 12,000 per year (maintenance + hosting) |
| Fit with firm processes | Low, limited configuration | Complete |
| Multi-software integration | Usually one vendor only | Practice software, banks, Peppol |
| Ownership of data and code | Vendor | Firm |
| Go-live time | 2 to 6 weeks | 10 to 16 weeks |
| Estimated break-even | Immediate | 18 to 30 months |
The decisive calculation is the recurring cost. A firm with 750 files paying EUR 4 per file per month spends EUR 36,000 a year. A custom tool at EUR 55,000 with EUR 8,000 of annual maintenance pays for itself in under two years, before counting the time saved.
E-invoicing: what the tool must handle
Under the EU VAT in the Digital Age (ViDA) package, structured e-invoicing becomes the norm, with Ireland planning a phased B2B mandate starting in November 2028 for large corporate taxpayers and extending to all VAT-registered businesses by 2030. France already applies its own mandate from 1 September 2026, which matters for any Irish firm with French clients. For an accounting firm, the challenge is twofold: automatically retrieve clients' invoice flows, and offer a billable compliance service.
| Requirement | Impact on the tool | Estimated extra cost (EUR excl. VAT) |
|---|---|---|
| UBL, Peppol BIS, Factur-X formats | Parsing and validation of structured data | 3,000 to 6,000 |
| API connection to one or more access points | Per-client flow retrieval | 4,000 to 10,000 |
| Digital reporting of transactions | Export and checks before submission | 2,000 to 5,000 |
| Invoice lifecycle statuses | Track submitted, rejected, paid | 1,500 to 4,000 |
| Legally valid archiving (6 years in Ireland) | Timestamped storage | 1,000 to 3,000 |
Mini case study
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Claire, managing partner of a 35-person accounting firm in Dublin, handles 820 client files. Her teams spend an average of 3 hours per file per year chasing, sorting and re-keying documents. She commissions a custom tool at EUR 58,000 excl. VAT (client portal, production tracking, practice software connector, e-invoice reception), plus EUR 9,000 a year for maintenance and certified hosting.
Result after one year: 2.5 hours saved per file, or 2,050 hours. At a loaded hourly cost of EUR 45, that is EUR 92,250 of freed capacity, redeployed to billable advisory work. The project pays back in 8 months, and the firm took on 60 new clients without hiring.
FAQ
How much does custom software cost for a 30-person accounting firm?
Expect EUR 30,000 to 55,000 excl. VAT for a collection portal, production tracking and one connector. With e-invoice reception and a second integrated system, the budget rises to EUR 65,000 to 80,000.
Can the tool connect to several practice software packages at once?
Yes, each connector is an independent module priced at EUR 6,000 to 20,000 depending on how open the vendor's API is. Xero has a well documented API, while desktop-based packages often need a partnership or an intermediate export.
Which hosting should we choose for client data?
EU hosting with an ISO 27001 certified provider costs EUR 150 to 600 per month. It meets GDPR requirements and professional body expectations on confidentiality.
How long does delivery take?
A standard project takes 10 to 16 weeks, with a first usable version in 6 to 8 weeks. Schedule go-live outside peak tax season, ideally between November and January in Ireland.
Is the tool ready for e-invoicing?
It can be if you include the access point module, for EUR 4,000 to 12,000 excl. VAT. It then retrieves your clients' invoices in structured format and feeds production directly.
Let's scope your project. Send us your number of client files, your practice software and your priorities: we will price a scope between EUR 30,000 and 80,000 excl. VAT with a 10 to 16 week 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.
