Supplier invoice portal with e-invoicing in Berlin (2026)

The verdict in three sentences

Since 1 January 2025, every German business must be able to receive structured e-invoices in B2B, and from 1 January 2027 companies with more than 800,000 EUR turnover must also issue them. For a 400-employee mid-sized company in Berlin, the safest route combines an e-invoicing service provider charging 0.10 to 0.50 EUR per invoice and, where volume and complexity justify it, a custom supplier portal at 30,000 to 70,000 EUR for everything the provider does not cover. The classic mistake is to think the portal replaces compliant e-invoice exchange: it complements it, it never substitutes for it.

What the German mandate really requires from a Berlin Mittelstand company

The rule is straightforward: domestic B2B invoices between German VAT-registered businesses must be issued as structured electronic invoices compliant with EN 16931, such as XRechnung or ZUGFeRD from version 2.0.1. A PDF sent by email no longer qualifies as an e-invoice once the transition period ends.

For an industrial or wholesale company in Berlin receiving 25,000 to 40,000 supplier invoices a year, reception is already handled once a provider is chosen. The real work sits downstream: matching against purchase orders, approval workflows, disputes and relationships with small suppliers.

Provider only or provider plus custom supplier portal: comparison

An e-invoicing provider ensures compliant exchange. It does not handle, or handles poorly, supplier onboarding, document requests (trade register extract, tax certificates, bank details), dispute tracking or giving suppliers visibility on payments.

The custom portal pays off above roughly 20,000 invoices a year, with more than 500 active suppliers and a dispute rate above 5%. Below that, a provider well integrated with the ERP is enough.

Detailed 2026 budget for a 400-employee company

Year one total with portal: 60,000 to 140,000 EUR. Without portal: 20,000 to 60,000 EUR.

Mini case study

Illustrative scenario: Katrin, CFO of a 400-employee wholesale company in Berlin, receives 32,000 invoices a year from 900 suppliers. Current processing cost is estimated at 9 EUR per invoice (keying, reminders, disputes), i.e. 288,000 EUR a year.

With a provider alone, integrated with the ERP, she targets 5 EUR per invoice: 160,000 EUR, a saving of 128,000 EUR. With the custom portal, which cuts disputes and supplier calls, she targets 3.50 EUR: 112,000 EUR, an extra 48,000 EUR saved per year. The portal, priced at 55,000 EUR plus 12,000 EUR yearly maintenance, pays back in about 16 months.

FAQ

Can a custom supplier portal replace compliant e-invoice exchange?

No, invoices must still be issued and received in an EN 16931 format through a compliant channel. The portal connects to your provider via API to improve the supplier experience.

How much does an e-invoicing provider cost for 30,000 invoices a year?

Offers usually range from 0.10 to 0.50 EUR per invoice, i.e. 3,000 to 15,000 EUR a year. Setup fees of 5,000 to 15,000 EUR are often added.

How long does the portal take to deploy?

Plan 3 to 5 months for a full portal, including 4 weeks of scoping with purchasing and accounting. A first release covering onboarding and payment tracking can ship in 8 to 10 weeks.

What about small suppliers not yet ready to issue e-invoices?

Smaller businesses only have to issue structured invoices from 1 January 2028. Until then, the portal can offer guided invoice entry that generates a compliant XRechnung file.

Do we redo the ERP integration if we switch provider?

Not if the integration goes through an intermediate API layer. This decoupling costs 10 to 15% more upfront but avoids paying another 10,000 to 25,000 EUR when switching.

Let's scope your project. Tell us your invoice volume, your ERP and the number of active suppliers, and we will price the portal, integration and timeline against your regulatory deadlines. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.