DATEV handover from weclapp: Rechnungsdatenservice, Buchungsdatenservice or CSV?

There are three main routes. In addition there are the Belegbilderservice (document image service), which only transfers PDF documents, and the master data export; the pricing page counts six export types in total because the CSV is counted in two variants. Which route fits is decided by your tax firm's setup, not by the ERP.

Rechnungsdatenservice 1.0. The interface transfers structured document data and digital documents to DATEV Unternehmen online (DATEV names the firm's accounting programs as the target) and turns them into booking suggestions (DATEV marketplace, weclapp entry). The technical basis is the XML interface online. From weclapp, sales and purchase invoices, credit notes and cash transactions go out. This route does not transfer master data. The tax firm reviews the suggestions and posts them.

Buchungsdatenservice. Here structured booking data and the associated digital documents arrive as booking entries that the tax firm takes over into DATEV accounting. The technical basis is the DATEV format. According to the help, weclapp also transfers bank transactions and general ledger entries, each with a document image.

CSV in DATEV format. weclapp creates a ZIP file with CSV files that your tax firm unpacks and imports. There are two variants. The journal-based variant contains the booking journal, general ledger master data and debtor and creditor master data, and also includes entries you capture via batch posting. The document-based variant exports only the documents created in weclapp with the stored default accounts; the invoices do not have to be posted beforehand.

For both data services the following applies in weclapp: accounting is set up, and the documents have the status "Posted" in the journal and are locked. According to the weclapp help, customers and suppliers need five-digit personal accounts: debtors from 10000 to 69999, creditors from 70000 to 99999. For the Buchungsdatenservice, the start of the fiscal year must also match in weclapp and DATEV.

You get the client number, advisor number and the length of the general ledger account numbers from your tax firm. Also agree with them which chart of accounts they use: weclapp includes the standard charts SKR03 and SKR04. The connection to DATEV works via sign-in, for example with SmartLogin. For security reasons it expires regularly, at the latest when you log out of weclapp, and you re-establish it as needed.

weclapp and DATEV describe the setup itself step by step; we link both below under sources. Ordering and activation of the data services happen at DATEV; who orders is something you clarify with your tax firm.

At month end a tax firm wants four things, whichever route you choose:

1. Documents. Every invoice and credit note as a document, cleanly assigned to the booking entry.
2. Booking batch. All booking entries of the month, with account, offset account, tax key and document link, in a format the tax firm reads in without manual work.
3. Payment matching. Which payment belongs to which open invoice. In weclapp this comes from open-item reconciliation and the automated booking of bank transactions. In DATEV it only comes along with the Buchungsdatenservice; with the Rechnungsdatenservice the tax firm matches using its own bank data, and the invoice number in the payment reference helps. In addition there is Zahlungsabgleich 4 weclapp from wals.pro: it books recognized bank transactions to open items. Zahlungsabgleich 4 weclapp breaks down bulk payouts and payment advices from payment service providers such as PayPal or American Express into individual payments and fees and assigns them to the invoices; a five-step scoring match rates each hit. We connect further payment service providers on request.
4. Bulk payouts as a transfer booking. A payout from Shopify Payments, PayPal or Klarna is not revenue but the payment flow for many orders. It belongs as a transfer booking between the payment provider account and the bank, via a transit or clearing account depending on the tax firm. Fees and refunds are shown separately. The VAT treatment of the fees is something you clarify with your tax firm.

This does not replace tax advice; accounts and booking rules are set by your tax firm.

At the client's request, tax advisors can get free access to the weclapp system (weclapp list price, as of October 2026). The pricing page lists the access in the accounting feature list and as a single license at €0. Tax advisor access is available in every package, including ERP Starter.

The access does not replace the DATEV handover. It can complement it, though, when the tax firm looks into the system itself. Which rights the access includes is something you set in weclapp; clarify this with your tax firm beforehand.

A fictional example: a shop with 3,000 orders a month and a tax firm that uses DATEV Unternehmen online. At month end the team locks the journal drafts, checks the counters "New documents" and "Incomplete documents", transfers in one batch and checks the log. Faulty documents, for example with an invalid personal account, are skipped by the transfer; for an invalid IBAN it reports an error. The team corrects the master record and transfers again.

Who is this relevant for? For online merchants and wholesalers with volume (ERP for online merchants), for SaaS, app and subscription providers (Accounting for SaaS and subscription business) and for IT service providers and MSPs.

On the e-invoicing obligation, which also lands in accounting: whether an e-invoice transfers the structured original or the PDF rendering is not described in the weclapp help; clarify this with weclapp and your tax firm before the e-invoice issuing obligation begins (stages 2027 and 2028).

• E-invoicing for subscription providers: how subscription invoices become e-invoices (XRechnung or ZUGFeRD) and which deadlines apply.
• E-invoicing in Austria: whether there is a B2B obligation in Austria, what ebInterface is and what the EU requires from 2030.