The verdict in three sentences
Manually keying hundreds of supplier invoices costs an SME 10 to 18 accounting hours per week and multiplies coding errors. An OCR + AI pipeline auto-extracts 95 to 99% of fields and is scoped between 12,000 and 38,000 EUR over 6 to 10 weeks. The key choice: off-the-shelf OCR SaaS or a custom pipeline integrated into your accounting.
OCR SaaS (Mindee, Rossum) or custom pipeline?
SaaS extraction APIs are excellent and fast to wire in. Custom is justified for atypical documents, high volumes or deep IS integration.
| Criterion | OCR SaaS (Mindee, Rossum) | Custom pipeline |
|---|---|---|
| Setup cost | 4,000 - 12,000 EUR | 12,000 - 38,000 EUR |
| Timeline | 3 - 6 weeks | 6 - 10 weeks |
| Cost per document | 0.05 - 0.30 EUR/doc | ~0.01 - 0.08 EUR/doc |
| Atypical documents | limited to models | fully adaptable |
| Accounting integration (Sage, Pennylane) | standard connectors | custom, deep |
| Confidentiality | vendor cloud | your hosting |
| Vendor lock-in | medium to high | none |
Many SMEs combine both: SaaS API for the extraction core, a custom layer for validation, coding and direct posting to accounting.
Extraction rate and cost per document
Quality depends on document type and the level of human control kept.
| Document type | Correct extraction rate | Processing cost (2026 order) |
|---|---|---|
| Standard supplier invoice | 97 - 99% | 0.02 - 0.10 EUR |
| Handwritten/degraded scan | 88 - 94% | 0.08 - 0.25 EUR |
| Purchase order | 95 - 98% | 0.03 - 0.12 EUR |
| Expense report | 92 - 97% | 0.05 - 0.15 EUR |
| Bank statement | 96 - 99% | 0.04 - 0.12 EUR |
Targeted human control (validating only anomalies) reaches 99%+ final reliability without re-keying everything.
Accounting hours saved
Return is first measured in time given back to the accounting team.
| Monthly invoice volume | Current manual time | Time after OCR+AI | Weekly saving |
|---|---|---|---|
| 300 invoices | ~10 h/wk | ~2 h/wk | ~8 h |
| 600 invoices | ~16 h/wk | ~3 h/wk | ~13 h |
| 1,000 invoices | ~24 h/wk | ~5 h/wk | ~19 h |
| 1,500 invoices | ~34 h/wk | ~7 h/wk | ~27 h |
Mini case study
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Antoine, CFO of a 60-employee construction SME in Toulouse, receives 750 supplier invoices/month, keyed by hand by 1.5 accountants. Kolonell delivers an OCR + AI pipeline wired to Pennylane for 28,000 EUR in 8 weeks, processing cost ~90 EUR/month.
Result: 15 h/week freed (15 x 32 EUR x 45 weeks = 21,600 EUR/yr), coding errors down 80%, invoice processing time cut 4x. ROI reached in about 13 months, with a markedly faster monthly close.
FAQ
Does OCR work on poor-quality scans?
On degraded scans or handwriting, the rate drops to 88-94%. We add a targeted human validation step on anomalies to secure final reliability above 99%.
SaaS or custom: what threshold?
Below ~500 invoices/month with standard formats, an API like Mindee or Rossum often suffices. Beyond that, or for deep accounting integration, custom becomes cost-effective.
Does accounting data stay confidential?
With custom, processing runs on your hosting or a GDPR-compliant EU cloud. No invoice feeds a third-party model.
How much do we really save?
On 600-1,000 invoices/month, you typically free 13 to 19 accounting hours per week, i.e. 18,000 to 27,000 EUR/yr, plus reduced coding errors.
Can it post directly into our accounting software?
Yes. The pipeline posts entries to Sage, Cegid, Pennylane or Odoo via API, with automatic PO/invoice/receipt matching.
Let's scope your project. Specify your monthly invoice volume, your document types and your accounting software: indicative budget 12,000-38,000 EUR by complexity. 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.
