The verdict in three sentences
A custom client portal for an accounting firm with 600 client files costs EUR 25,000 to 60,000 excl. VAT in 2026, delivered in 3 to 5 months, with document upload, receipt OCR and automated reminders. Compared with an off-the-shelf tool billed at EUR 8 to 20 per file per month, i.e. EUR 57,600 to 144,000 per year for 600 files, a custom build pays off in 6 to 18 months once you exceed 300 active files. Health-data hosting is not required for accounting documents, but EU hosting (France for French firms) and a GDPR processing agreement are effectively mandatory.
The real cost of manual chasing
In a 600-file firm, staff spend on average 10 hours a week requesting bank statements, purchase invoices and expense receipts by email, phone or WhatsApp. Over 46 working weeks, that is 460 hours a year, about EUR 18,400 of staff time at EUR 40 per loaded hour, before counting late year-end accounts and late-filing penalties.
A well-designed portal removes most of this work: each client sees the list of expected documents, uploads a photo from their phone, OCR extracts date, amount, VAT and supplier, and the system automatically sends reminders at D+3, D+7 and D+14.
| Function | Without portal | With portal | Estimated gain |
|---|---|---|---|
| Client reminders | 10 h per week | 2 h per week | 368 h per year |
| Receipt data entry | 3 to 4 min per document | 30 to 60 s with OCR | 60 to 75% of the time |
| Missing documents at closing | 15 to 25% of files | 5 to 8% | Accounts delivered earlier |
| Email exchanges | Scattered, untraceable | History per file | Fewer disputes |
| Average monthly collection time | 18 days | 7 days | 11 days saved |
Custom build or off-the-shelf: the numbers
Off-the-shelf tools are fast to deploy but charge per file, and their reminder logic or document taxonomy does not always fit your processes. A custom build requires an upfront investment but then costs a fixed maintenance fee.
| Criterion | Off-the-shelf tool | Custom portal |
|---|---|---|
| Upfront cost | EUR 0 to 3,000 setup | EUR 25,000 to 60,000 excl. VAT |
| Recurring cost for 600 files | EUR 4,800 to 12,000 per month | EUR 600 to 1,500 per month (maintenance + hosting) |
| Time to deploy | 2 to 6 weeks | 3 to 5 months |
| Custom document lists | Limited | Full, per engagement type |
| Link to production software | Standard connectors | Custom API (Cegid, ACD, Pennylane, Inqom) |
| Branding | Firm logo | Firm colours, own domain name |
| Ownership of data and code | Vendor | Firm |
What a EUR 25,000 to 60,000 budget covers
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| Module | Indicative price excl. VAT |
|---|---|
| Secure client area (strong authentication, delegate management) | EUR 5,000 to 9,000 |
| Mobile and web upload, drag and drop, photo | EUR 4,000 to 8,000 |
| OCR and extraction (date, amount, VAT, supplier) | EUR 5,000 to 12,000 |
| Document lists per engagement and automated reminders | EUR 3,000 to 7,000 |
| Staff dashboard and overdue tracking | EUR 3,000 to 8,000 |
| Production software connector | EUR 3,000 to 10,000 |
| EU hosting, encryption, logging, backups | EUR 2,000 to 6,000 |
Mini case study
Marc, partner at a 600-file accounting firm in Nantes, compares two options over 3 years. The off-the-shelf tool at EUR 10 per file per month costs EUR 72,000 a year, i.e. EUR 216,000 over 3 years. The custom portal at EUR 42,000 excl. VAT, plus EUR 1,100 per month for maintenance and hosting, totals EUR 81,600 over 3 years. The gap reaches EUR 134,400. Adding the 368 hours of chasing saved each year (about EUR 14,700 per year), the portal pays for itself in under 8 months.
FAQ
How much does an accounting client portal cost in 2026? EUR 25,000 to 60,000 excl. VAT for a custom build, depending on OCR, the number of connectors and the complexity of document lists. Add EUR 600 to 1,500 per month for maintenance and hosting.
Is health-data-grade hosting required? No, accounting documents are not health data. However, EU hosting, file encryption and a GDPR processing agreement are expected by professional bodies and by your clients.
Is OCR reliable? On good-quality invoices and receipts, current engines correctly extract 90 to 97% of key fields. Staff validate uncertain cases, which is still 3 to 5 times faster than full manual entry.
From how many files does a custom build pay off? Around 250 to 300 active files, when the off-the-shelf subscription exceeds EUR 10 per file per month. Below that, an off-the-shelf tool remains cheaper.
Will clients actually use it? With photo upload from the phone and automated reminders, firms usually see 60 to 80% adoption within the first 6 months.
Let's scope your project. We scope your document upload portal with OCR, reminders and a connector to your production software, at EUR 25,000 to 60,000 excl. VAT with delivery in 3 to 5 months. 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.
