The verdict in three sentences
A company processing 2,400 supplier invoices a month loses dozens of hours every month to follow-up calls, manual entry and matching disputes. A custom supplier portal, connected to your ERP and to your e-invoicing channel (XRechnung, ZUGFeRD), costs 30,000 to 60,000 EUR excluding VAT and goes live in 4 to 5 months. Typical gains are around 40% fewer supplier calls and 8 to 12 days faster payment, which also protects you from late payment charges.
Why a portal now: the German e-invoicing timeline
Since 1 January 2025, every German business must be able to receive structured e-invoices (XRechnung or ZUGFeRD). Companies above 800,000 EUR turnover must issue them from January 2027, and all others from January 2028. The e-invoicing channel carries the invoice, but it does not tell the supplier where their payment stands or why their invoice is blocked. That is exactly what a supplier portal does.
| Need | E-invoicing channel only | Custom supplier portal |
|---|---|---|
| Receiving XRechnung, ZUGFeRD, UBL invoices | Yes | Yes, through the channel |
| PDF upload by small suppliers | Limited | Yes, with OCR and checks |
| Status visible to the supplier (received, approved, paid) | Basic delivery status only | Yes, with expected payment date |
| Purchase order, goods receipt, invoice matching | No | Yes, 3-way match |
| Disputes and credit notes | No | Yes, thread per invoice |
| Bank details and documents update | No | Yes, with dual approval |
| Indicative 2026 cost | 0.10 to 0.50 EUR per invoice | 30,000 to 60,000 EUR + maintenance |
Budget breakdown
The price depends mainly on the ERP (SAP, Microsoft Dynamics, DATEV-linked systems, Sage) and on the number of approval rules.
| Module | Content | Indicative budget |
|---|---|---|
| Supplier space | Registration, profile, legal documents, secure bank details | 5,000 to 9,000 EUR |
| Invoice upload and tracking | PDF or ZUGFeRD upload, OCR, real-time statuses | 6,000 to 12,000 EUR |
| ERP connector | Reading purchase orders, receipts, postings and payments | 7,000 to 15,000 EUR |
| E-invoicing connector | XRechnung / ZUGFeRD ingestion and status messages | 4,000 to 8,000 EUR |
| Internal workflow | Buyer, accounting and CFO approval, amount thresholds | 4,000 to 9,000 EUR |
| Disputes and messaging | Thread per invoice, attachments, automatic reminders | 2,500 to 5,000 EUR |
| Security | Internal SSO, supplier two-factor authentication, audit log | 1,500 to 2,000 EUR |
A first version with upload, statuses and a read-only ERP connector comes in around 30,000 EUR. The full scope with 3-way matching, multi-level workflow and disputes approaches 60,000 EUR. Annual maintenance runs at 5,000 to 9,000 EUR.
Timeline and risks to manage
Allow 4 to 5 months: 4 weeks of scoping with accounts payable, 10 to 12 weeks of development, and a 3 to 4 week pilot with 30 to 50 suppliers. The biggest risk is bank detail fraud: the portal must enforce internal dual approval and a call-back check on any new bank account. The second risk is adoption: half your suppliers will only log in if reminder emails take them to their status in one click.
Mini case study
Thomas, CFO of an industrial company in Berlin, receives 2,400 invoices a month and his team handles about 600 follow-up calls and emails monthly at 8 minutes each, or 80 hours a month. With the portal, 40% of these requests disappear: 32 hours saved per month, roughly 1,400 EUR of loaded cost.
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Average payment time drops from 52 to 42 days. In Germany, late B2B payments trigger a 40 EUR flat fee per invoice plus statutory interest; avoiding 150 late invoices a month saves 6,000 EUR monthly in fees alone. For a 48,000 EUR portal, payback comes in 6 to 7 months (48,000 / 7,400 EUR of monthly gains).
FAQ
How much does a custom supplier portal cost in 2026?
Between 30,000 and 60,000 EUR for a mid-sized company, depending on the ERP and workflow depth. Annual maintenance is 5,000 to 9,000 EUR.
Does the portal replace our e-invoicing channel?
No. Receiving structured e-invoices has been mandatory in Germany since January 2025; the portal plugs into that channel and adds tracking, disputes and supplier documents.
Which ERPs can you connect?
SAP, Microsoft Dynamics, Sage and most ERPs with an API or scheduled exports. The connector accounts for 7,000 to 15,000 EUR of the budget.
How do we prevent bank detail fraud?
Internal dual approval, verification with the supplier through a separate channel and a 72-hour payment hold on any new account. This module costs under 2,000 EUR.
How long does supplier onboarding take?
A pilot with 30 to 50 suppliers takes 3 to 4 weeks; 70 to 80% of active suppliers are usually registered within 3 months.
Let's scope your project. Tell us your ERP, e-invoicing setup and monthly invoice volume, and we will quote a portal delivered in 4 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.
