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# Send Lexware Office payment reminders for overdue invoices

> Find overdue Lexware Office invoices weekly, send Zahlungserinnerungen or Mahnungen by your own rule and keep the rest for you. Runs from an agent.

Source: https://cotlet.dev/integrations/lexware-office-api-mcp-server/send-payment-reminders

Overdue invoices pile up in the Belege list in orange, and sending each reminder means opening the invoice, adding the fee, checking the text and sending it, so it waits until the end of the month.

Cotlet does it in your own Lexware Office (lexoffice) account with list\_documents, get\_document and send\_payment\_reminder, called by your AI agent, an n8n workflow or a script.

[Sign up free](https://cotlet.dev/app/signup?app=lexware-office) [All Lexware Office (lexoffice) tools](https://cotlet.dev/integrations/lexware-office-api-mcp-server.md)

Hosted · nothing to install or maintain

## Can Lexware Office (lexoffice) do this on its own?

Lexware Office has the Mahnen action in the app, which prepares one reminder per invoice (checked 14 Oct 2026). Its public API, available from version XL, has no endpoint for reminders and no way to send a document by email. Nothing in Lexware Office sends reminders on a schedule or by a rule such as days overdue.

## How you do it in Lexware Office (lexoffice) today

1. Open Belege in the main menu and check Überfällige or Offene Belege in the left navigation; overdue documents are marked in orange in every list.
2. Click the invoice, open Weitere Aktionen (the three dots) and choose Mahnen, which only works for invoices created in Lexware Office, not imported ones.
3. Adjust the document title and introductory text, load a saved text template if you use one, and add a fee with + Artikel by picking the item type Mahngebühr.
4. Click Vorschau to check the document, then Speichern and Versenden to send it by email or post.
5. Open the invoice later and scroll to the Mahnungen section in the details to see which reminders already went out.

## How to send Lexware Office payment reminders for overdue invoices

Prompt

```
Every Monday, list the overdue invoices in Lexware Office. For invoices more than 14 days overdue, send a payment reminder with a 5 EUR fee. Show me the others with the days overdue and do not touch them.
```

1. 01  
### Pull the overdue list  
Your agent calls list\_documents with type invoice and status overdue and pages through the cursor, so the whole backlog is judged in one run, not only the first page.
2. 02  
### Read each invoice before acting  
get\_document returns the open amount, the due date and the Mahnungen already sent. An invoice that has a reminder from the last seven days is skipped, so nobody gets two mails in a week.
3. 03  
### Apply your rule  
Invoices past the number of days in your prompt go to the reminder pile, with the fee you named. Anything younger, or any invoice to a customer you listed as a key account, is only reported.
4. 04  
### Send the reminder  
send\_payment\_reminder opens Mahnen on the invoice, uses your saved text template, adds the Mahngebühr line and sends by email. It asks for your OK per call by default, because the customer receives it.
5. 05  
### Report what moved  
The agent lists each reminder sent with the amount and days overdue, and each invoice it left alone with the reason. Imported invoices that Mahnen cannot handle are listed separately.

### What you get back

Example data

```
Overdue invoices: 7
Reminders sent 3:
- RE1031 Nordlicht Design GmbH, 1,130.50 EUR, 21 days overdue, fee 5.00 EUR
- RE1034 Becker Consulting, 2,380.00 EUR, 18 days overdue, fee 5.00 EUR
- RE1036 Studio Fjord, 595.00 EUR, 16 days overdue, fee 5.00 EUR
Left for you 4: 2 under 14 days overdue, 1 reminded last Thursday, 1 imported invoice
```

### Other ways to ask

- Send a friendly Zahlungserinnerung at 7 days overdue and a Mahnung with a fee at 21 days, using my saved texts.
- List overdue invoices over 1,000 EUR with the customer's contact person, but do not send anything.
- Every Friday, remind customers whose invoice is more than 10 days overdue and email me the list afterwards.

## What Lexware Office (lexoffice) allows, and what to know first

- Lexware Office shows the Mahnen action only for invoices created in Lexware Office, not for imported ones.
- The reminder email contains a link to the reminder, and that link does not update when the customer pays later, so Lexware advises resending the paid invoice then.
- Lexware Office stores reminders inside the invoice: they appear in the Mahnungen section of its details and are not separate documents.
- A reminder fee is added as an item of type Mahngebühr, and the total updates automatically.
- Overdue documents are marked with orange text in all overview lists, and Überfällige is its own filter under Belege.

send\_payment\_reminder asks for your OK by default. To run it weekly without you, switch confirmation off for that tool in your dashboard.

Sources: [Lexware Office Help: Zahlungserinnerungen und Mahnungen erstellen](https://help.lexware.de/de-form/articles/547985-zahlungserinnerungen-und-mahnungen-erstellen) · [Lexware Office Help: Rechnungen & Angebote](https://help.lexware.de/de-form/collections/1335664-rechnungen-angebote) · [Lexware Office API documentation](https://developers.lexware.io/docs/)

## Call send\_payment\_reminder from a script

curl

```
curl -X POST https://cotlet.dev/api/v1/lexware-office/documents/d_9c31be/payment-reminders \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"fee_amount":5}'
```

Example response

```
{
"document_id": "d_9c31be",
"number": "RE1031",
"reminder_number": 1,
"fee_amount": 5,
"sent_to": "buchhaltung@nordlicht.example",
"sent_at": "2026-10-14T08:02:00+02:00"
}
```

MCP: add https://cotlet.dev/mcp/v1 with the same key; the call is lexware\_office\_write → send\_payment\_reminder. Example data.

[Schedule it in n8n, Make, Zapier or cron](https://cotlet.dev/integrations/lexware-office-api-mcp-server.md#automations)

## Lexware Office (lexoffice) tools this automation uses

__Cotlet Lexware Office (lexoffice) tools used to send Lexware Office payment reminders for overdue invoices__
| Tool | Parameters |
| ----------------------- | ---------------------------------------------------- |
| list\_documents | type, status, contact\_id, from\_date, limit, cursor |
| get\_document | document\_id |
| send\_payment\_reminder | document\_id, fee\_amount, intro\_text |

[All 14 Lexware Office (lexoffice) tools with descriptions](https://cotlet.dev/integrations/lexware-office-api-mcp-server.md#tools)

## Frequently asked questions

### Is it safe to connect Lexware Office (lexoffice) to Cotlet?

Yes. You sign in to Lexware Office (lexoffice) yourself, in your own Cloud Browser in the EU, and we never save your password. Your agents only get Lexware Office (lexoffice) once you enable it, every background request is listed, and the browser profile is stored encrypted with AES-256-GCM, the cipher 1Password uses for its vaults. The AI model never sees a login, posts and messages wait for your OK, and Disable for agents cuts access in one click. Independent scanners grade cotlet.dev A+ on Qualys SSL Labs, securityheaders.com and Mozilla Observatory; live results are on https://cotlet.dev/security.

## More Lexware Office (lexoffice) automations

- [Create and send Lexware Office invoices from a list](https://cotlet.dev/integrations/lexware-office-api-mcp-server/create-and-send-invoices.md)
- [Upload receipts to Lexware Office automatically](https://cotlet.dev/integrations/lexware-office-api-mcp-server/upload-receipts-for-bookkeeping.md)
- [Lexware Office (lexoffice) API and MCP server: every tool](https://cotlet.dev/integrations/lexware-office-api-mcp-server.md)
- [All use cases](https://cotlet.dev/use-cases.md)

## Give your agent access to Lexware Office (lexoffice).

Free 7-day trial with 2,000 credits, no card needed. Cotlet is independent and not affiliated with Lexware Office (lexoffice).

[Sign up free](https://cotlet.dev/app/signup?app=lexware-office)

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## For AI agents: sign your user up

Is your user asking you to sign them up for Cotlet? You can do it for them, no account or key needed.

1. Read the fields and their allowed values: GET https://cotlet.dev/api/v1/access-requests
2. Ask the user for each value: email, apps, what you will do with them. If they leave the password to you, generate a strong one and show it to them.
3. Show the user what you will send, then POST it as JSON to https://cotlet.dev/api/v1/access-requests.

One call creates the account and sends the access request; we email the user when access is granted.