The Lexware Office interface hands customers, suppliers, invoices, employees and receipts from ZEP over to Lexware Office. Lexware Office is the web accounting application by Haufe-Lexware. ZEP remains the leading system: the data flows from ZEP to Lexware Office only, there is no return channel.
Data direction: ZEP → Lexware Office
Product Line Availability
Note: The Lexware Office interface is included from ZEP Operations upwards, because it builds on the Billing area. No additional booking is required.
The interface requires the Invoicing area, as it transfers invoices and receipts. Without invoicing, no data arises in ZEP that could be transferred to Lexware Office.
Setup and configuration are reserved for administrators.
Distinction from the Lexware Export Format
ZEP offers a second route carrying the Lexware name, and the two have nothing to do with each other. Confusing them means looking for data in the wrong place.
Lexware Office interface: you set it up under Administration > Interfaces > Interface Marketplace. ZEP transfers the data hourly and by itself, directly into the Lexware Office web application.
Lexware export format in Export for Accounting: you select it under Administration > Export for Accounting. ZEP produces a file of accounting records which you download and read into a Lexware desktop program. That route is described in the article Export Formats – DATEV, Lexware and General.
Both routes can run side by side. They know nothing of each other, so data going one way does not also go the other.
Requirements
For the setup you need:
Access to the Interface Marketplace in ZEP
The Invoicing area, so that invoices and receipts exist
An account in Lexware Office with access to the Public API
The API key created there
Tip: You create the API key in Lexware Office under Extensions > Public API, not in ZEP. It applies per tenant. If you run several tenants in Lexware Office, you need a separate key for each one.
Setting Up the Interface
In ZEP, open Administration > Interfaces > Interface Marketplace. Select the Lexware Office card in the Finance & Taxes category and click Configure. Once the interface has been set up, the button reads Manage. The form has four sections.
Authentication Settings
Enter the API key from Lexware Office here. It is the only mandatory field in the entire form. Use Test connection to check whether ZEP reaches Lexware Office with this key. If the test succeeds, ZEP activates the interface right away. If it fails, ZEP marks the credentials as invalid and transfers nothing.
Export Data
Here you determine which kinds of data are transferred. Four checkboxes are set by default, one is not:
Export customers as debtors — set. ZEP customers become debtor contacts in Lexware Office.
Export suppliers as vendors — set. Suppliers with a supplier number are transferred. If a supplier is also a customer, ZEP adds the vendor role to the existing contact instead of creating a second one.
Export invoices — set. Billed invoices are transferred and become finalized invoices in Lexware Office.
Export employees as vendors — set. A requirement for exporting receipts.
Export vouchers (expense reports) — not set. Only switch this checkbox on once you have mapped the posting categories, see below.
Employee Vendors
In the Vendor number source field you determine which number from ZEP is used as the vendor number in Lexware Office:
Personnel number — the default. ZEP transfers every employee who has a personnel number.
Vendor number — ZEP transfers only employees for whom a vendor number has been set explicitly. This is the narrower route if only part of the workforce submits expenses.
Receipts and Posting Categories
This section is only needed if you transfer receipts. Lexware Office requires a posting category for every incoming voucher, and those categories come from your Lexware tenant, not from ZEP. You therefore provide two entries:
Receipt type → posting category — a text field in which you enter the identifier of the Lexware category for each ZEP receipt type, for example travel expenses and hospitality.
Default posting category (fallback) — one identifier for all receipt types without their own mapping.
Warning: If ZEP finds neither a mapping nor a default category for a receipt type, it does not transfer the receipt and records the reason. The same happens if the identifier entered does not exist in Lexware Office. Map the categories before you set the checkbox for receipts.
What Is Transferred
After setup, the synchronisation runs hourly and by itself. In every run, ZEP transfers the contacts first and the invoices and receipts afterwards, so that the recipients already exist in Lexware Office.
Customers, Suppliers and Employees
Customers become debtor contacts, suppliers and employees become vendor contacts. ZEP creates employees as a person with first and last name, not as a company. If a contact was deleted in Lexware Office, ZEP creates it again in the next run.
Invoices
Invoices with the status billed are transferred and become finalized invoices in Lexware Office. Planned and released invoice items stay in ZEP until the invoice is billed.
If you cancel an invoice in ZEP that has already been transferred, ZEP creates a credit note in Lexware Office for the original amount, introduced by the text "Gutschrift zur Rechnung" and the invoice number. The original invoice in Lexware Office remains unchanged, and an invoice never receives two credit notes.
Warning: An invoice that has been transferred is not updated again. Finalized documents are immutable in Lexware Office. Later changes in ZEP only reach Lexware Office by cancelling the invoice and issuing a new one.
Receipts
Released and billed receipts are transferred. They become incoming vouchers in Lexware Office whose voucher number carries the ZEP prefix. The amounts are transferred gross and grouped by tax rate. A receipt with a negative total becomes a credit note instead of an incoming invoice.
Note: A receipt requires the person concerned to already exist as a vendor contact in Lexware Office. In the first run after switching the option on, receipts therefore often stay behind and go over in the next run. The same applies to an invoice whose customer has not been transferred yet.
Monitoring the Transfer
On the detail page of the interface, the dashboard shows when the last synchronisation ran, how many records it covered and how many were skipped. Latest errors lists the messages of failed runs.
A failed run is not repeated immediately. The next hourly run picks up the outstanding records, so a single failure resolves itself.
Limits of the Transfer
Four points matter when working with the interface:
No return channel. Lexware Office writes nothing back to ZEP. If you mark an invoice as paid there, the status in ZEP remains unchanged.
An invoice goes over once. Changes made after the transfer do not follow.
No documents. What is transferred are the accounting details, not the invoice PDF, the e-invoice or the image of a receipt.
Lexware sets the pace. Lexware Office accepts two requests per second. A large initial volume therefore spreads across several hourly runs.