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AI around DATEV: invoices, e-invoices and receipts for the tax advisor
DATEV is how German bookkeeping reaches the tax advisor. The business collects receipts and invoices in DATEV Unternehmen online or sends them over, the Steuerberater books them in Kanzlei-Rechnungswesen, and the whole relationship runs on DATEV's formats and permissions. The searches are German and specific ('datev ki', 'datev schnittstelle einrichten', 'datev schnittstellenpartner', 'eingangsrechnungen automatisieren'), and most AI tools built for English-speaking markets simply do not handle them.
E-invoicing makes this urgent. German businesses have had to be able to receive structured e-invoices since 1 January 2025, and issuing becomes mandatory from 1 January 2027 for companies with prior-year turnover above EUR 800,000 and from 1 January 2028 for everyone, in EN 16931 formats such as XRechnung and ZUGFeRD. Billing software that cannot produce them has less than four months left.
Everything in this hub works beside DATEV, not inside it: e-invoice intake that validates and routes the XML, issuing XRechnung and ZUGFeRD from a legacy system, supplier invoice processing, and document chasing for tax firms waiting on their clients' receipts.
What to build around DATEV
An e-invoice layer that lets an old ERP issue XRechnung and ZUGFeRD before 2027
Reads invoice data from the ERP you already have, maps it to EN 16931, generates XRechnung or ZUGFeRD, validates every file with KoSIT and sends it by email or Peppol.
The existing ERP or billing system / KoSIT validator / Email (Outlook or plain SMTP) / Peppol access point / DATEV
Receiving XRechnung, ZUGFeRD and Peppol invoices without retyping a single field
Structured e-invoices end the retyping, not the work: this pipeline validates them, renders them for approvers, matches them to orders and archives the original XML.
Peppol access point / Outlook or Gmail AP inbox / KoSIT validator / DATEV / Xero
Supplier invoices from inbox to ledger, with the checks a good controller would do
Reads supplier invoices from the AP inbox, matches them to purchase orders and goods receipts, and holds any invoice whose bank details changed until someone calls.
Outlook (Microsoft 365) / Xero / QuickBooks Online / DATEV / NetSuite
Chasing clients for receipts and bank statements without an accountant doing the chasing
A per-client checklist of what should arrive each month, polite reminders that name exactly what is missing, and every photo and PDF filed against the right booking.
DATEV / Xero / QuickBooks Online / WhatsApp Business Platform / Gmail
Supplier invoices turned into live recipe costs for a multi-site restaurant group
Every supplier invoice becomes current ingredient prices, so recipe costs stay live, price creep gets caught, and substitutions reach the chef before service.
WhatsApp Business Platform / Invoice inbox and e-invoices / DATEV / Xero / POS (Lightspeed, orderbird, Toast)
How data actually gets into DATEV
The DATEV format still carries the bookings
Booking batches travel as CSV files in the DATEV format, with an EXTF header naming the advisor and client numbers, the fiscal year and the account length, then SKR03 or SKR04 accounts and tax keys per line. It is strict and old, and still the most common handover.
Online interfaces need onboarding
DATEV's cloud interfaces for documents and booking data are open to registered partners, and each client authorizes access with its own DATEV login. I plan that onboarding into the timeline rather than discovering it in week three.
The advisor owns the chart of accounts
Account and tax key proposals follow the advisor's conventions and earlier bookings for the same supplier. The system proposes with a reason, the firm decides, and its corrections become the next precedent.
Originals are kept as received
GoBD expects the original document to be archived unchanged and findable. The build stores each file exactly as it arrived, XML included, and links every proposal back to it.
No MCP server, no open write API
DATEV has no server in the official MCP registry and no open API that lets any tool post bookings. A product that promises to book straight into DATEV deserves a close look at how.
What e-invoicing changes, and what stays with the Steuerberater
Validate before anyone reads it
Incoming XRechnung files are checked against the official KoSIT validator and the German business rules before anything is booked. An invalid invoice goes back to the supplier with the reason instead of being keyed by hand.
Leitweg-ID for public customers
Invoices to German public authorities need the buyer's Leitweg-ID and travel through the federal or state portals or Peppol. Issuing builds check the ID before sending, because a missing one means a rejected invoice.
Legacy billing gets a converter
When the invoicing software cannot produce EN 16931 XML, a converter builds XRechnung or ZUGFeRD from its data, validates it, and sends it by email or Peppol, with no change to how staff invoice.
Tax judgment stays with the advisor
Reverse charge under section 13b UStG, intra-EU acquisitions and unusual items are only ever proposals. The Steuerberater signs the return, so the Steuerberater decides.
Frequently asked questions
Does DATEV have an API for AI tools?
DATEV offers interfaces for documents and booking data through its partner program, and the DATEV format for booking batches remains the common handover. There is no official MCP server and no open API that lets any AI tool post bookings. Custom work therefore prepares, validates and delivers data through those interfaces, and the tax advisor stays in control of what is booked.
How do I automate incoming invoices into DATEV?
Collect invoices from email, upload and e-invoice channels in one place, validate XRechnung and ZUGFeRD files, extract the PDFs, and match each invoice to its order and delivery. The system proposes account and tax key with a reason, routes approval by amount, and hands the approved result to DATEV with the original attached, so a person approves before anything is booked.
What do German businesses need for e-invoicing by 2027?
Receiving structured e-invoices has been required since 1 January 2025. From 1 January 2027, companies with prior-year turnover above EUR 800,000 must also issue them, and from 1 January 2028 everyone must, in EN 16931 formats such as XRechnung or ZUGFeRD. If your billing software cannot produce these, a converter layer is usually faster than replacing it.
Can AI do the bookkeeping for our Steuerberater?
It can do the preparation: collect documents, check completeness, validate e-invoices, and propose bookings with reasons in the firm's chart of accounts. The Steuerberater still reviews and books, and carries the professional responsibility. What changes is that the firm receives complete, checked documents instead of a shoebox and a list of questions.
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