Payment Reminders That Send Themselves: Semi-Automated Dunning

Writing invoices has long been automated in most companies. Following up often has not. Open items are reviewed once a month, and reminders are written by whoever has time. Yet dunning is an almost perfect fit for automation: clear deadlines, fixed stages, one unambiguous data source. The only delicate moment is when a reminder turns into an escalation.

The starting point

Creditreform analyses real payment data from a shared data pool. In the first half of 2026, the average payment term in Germany was 32.21 daysD, the highest since 2019. Overdue invoices were paid 8.14 daysD late on average. In total, it took 40.35 daysD for the money to arrive.

In the 2026 Atradius survey, 87 % of companies surveyedU in Germany report late payments from business customers. The sample is small: 210 firms, most of them with fewer than ten employees. The reasons are revealing: half cite customers' liquidity problems, a third internal approvals at the customer. The first reminder should therefore make paying easy, with an invoice copy, order number and payment link.

The legal situation in Germany in five points

• Default: A reminder after the due date puts the debtor in default (Section 286(1) of the Civil Code). Without a reminder, default occurs no later than 30 days after the due date and receipt of the invoice. For consumers, this only applies if the invoice says so.
• Default interest: It is 5 percentage points above the base rate, and 9 percentage points in business-to-business transactions (Section 288 of the Civil Code). The base rate has been 1.52 %A since 1 July 2026. In B2B, that makes 10.52 % a year.
• Flat fee: Businesses can additionally charge other businesses a flat default fee of 40 EUR. Clauses that exclude default interest in advance are invalid.
• Court dunning procedure: The application can be filed online, for example with the electronic ID card. Since June 2025, the court fee has been at least 38 EURR.
• Debt collection: The creditor can only recover a collection agency's costs from the debtor up to the amount of lawyers' fees (Section 13e of the Legal Services Act).

The planned EU regulation with a fixed 30-day payment term has been stuck in the Council since 2025. It has not been adopted.

The workflow

The decisive step comes before every reminder: the daily match against the bank account. Nothing damages a customer relationship faster than a reminder for an invoice that was paid long ago.

Where AI helps and where it does not

Rules do the main work: due dates, stages, matching against the bank account. None of that needs AI. It becomes useful in two places. First, for payments with an unclear reference: the AI suggests the matching invoice, a person confirms. Second, for replies to reminders, which it classifies and routes.

Assign the customer's reply to our payment reminder to one category: PAID (payment claimed, with date), PROMISE (payment announced, with date), DISPUTE (service or invoice disputed), INVOICE_MISSING, INSTALMENTS, OTHER. Output category, any date mentioned and a one-sentence reason as JSON. If the category is not clear, choose OTHER. Do not reply to the customer.

Fixed rules follow from this. A dispute stops the dunning run and creates a ticket. A promise to pay pauses it until three days after the date given. If the invoice is missing, it is sent again immediately.

What the software can do

• SAP S/4HANA: The dunning run generates a dunning proposal that accounting can edit before sending.H
• DATEV: Three dunning levels, sending by email or print, interest and fees are calculated. DATEV does not mention fully automatic sending.H
• Lexware Office: According to its help pages, there is currently no automatic sending of dunning letters. A partner add-on provides it.H
• sevDesk: Dunning letters are created with one click and, according to its help pages, sent manually.H
• Stripe: Automatic reminders before, on and after the due date, with the invoice page serving as the payment link.H
• GoCardless: Failed direct debits are collected again on a more favourable day. The provider states an average success rate of 71 %H, without a methodology.
• n8n or Make: They connect accounting, bank and email when the accounting software does not send automatically itself.

Limits and risks

• Stop rules first: Disputes, instalment plans and ongoing clarifications must halt the dunning run immediately.
• Key accounts: Before stage 2, the workflow informs sales.
• Consumers: Different interest rates apply to them, and the 30-day rule only with a notice on the invoice.
• Data protection: Before handing over to a collection agency, clarify on what legal basis and under which contract the data flows.
• Where the numbers come from: Creditreform analyses a data pool, Atradius a small survey. The product information comes from the vendors.

How to start

1. Export the open items of the last twelve months and count how many were paid within a week of the first reminder.
2. Define stages, deadlines and stop rules on one page, together with sales.
3. Turn on the daily bank match before anything is sent automatically.
4. Automate only stage 1 at first. From stage 2 on, it stays a proposal that accounting approves for four weeks.
5. Measure the average number of days late and the share of disputes.

Sources

1. DCreditreform: Payment indicator Germany, summer 2026
2. UAtradius: Payment Practices Barometer Germany 2026
3. RGerman Civil Code, Section 286 (default of the debtor)
4. RGerman Civil Code, Section 288 (default interest and other damage)
5. ADeutsche Bundesbank: Base rate as of 1 July 2026
6. RGerman Court Fees Act, schedule of costs
7. RGerman dunning courts: Ways to file
8. RGerman Legal Services Act, Section 13e
9. REuropean Parliament: Procedure 2023/0323(COD), late payment
10. HSAP Learning: Executing the dunning process
11. HDATEV: Dunning
12. HLexware Office: Payment reminders and dunning letters
13. HStripe: Invoice reminders
14. HGoCardless: Success+