Documents to your tax adviser via DATEV: how Valued sends them

If your tax adviser works with DATEV, you no longer have to forward every PDF yourself. Valued can send documents directly to the DATEV mandate your adviser keeps for you. The connection is built in two steps: first by e-mail, through the address DATEV gives each mandate, then through DATEV's programming interface. Every transmission is logged, so that you can see later what went where and when. Since 15 October 2026 the public demo shows the DATEV connection as well, which means you can try it before you subscribe.

This article explains why completeness is the point, where the documents land at the firm, what each of the two steps does, and what the connection does not take off your hands.

Why the documents have to arrive complete

A tax adviser books and declares what reaches the firm. Nothing more. Whatever is missing from the file is missing from the return, and nobody notices until a question comes back, a correction has to be filed, or the tax comes out wrong.

For an investor with private assets the volume is larger than it looks. Take six fund commitments. Each fund sends four quarterly reports a year, say two capital calls and one distribution notice: seven documents per fund, 42 in total. Add the annual tax certificates of three depots and two statements for a rented flat, a loan statement and a service-charge statement. That is 47 documents in one year, arriving from a dozen senders, by e-mail, through portals and by post.

Forward 46 of them and you have done 98 per cent of the work. The one that is missing may still be the one that matters. If it is a distribution notice for EUR 50,000, the return is prepared without it, and the question whether that amount was capital paid back or income is never asked. Many investors hold such assets through an asset-holding GmbH, which adds a second set of books and a second file at the firm.

Completeness is therefore less a question of diligence than of route. Documents that leave the place where they are collected by a fixed path, without anyone having to remember them, arrive more reliably than documents forwarded by hand in March.

Where documents land at a DATEV firm

DATEV's own figure is that more than two million German companies keep their financial accounts with DATEV software. For a firm's clients the meeting point is usually DATEV Unternehmen online. There, each client has a mandate, and the firm's staff work from the documents filed in that mandate.

Documents can reach it in several ways. They can be dragged into the web interface or sent as a PDF by e-mail. DATEV also distinguishes file-based routes, online data services, programmatic interfaces and ready-made connections offered through the DATEV marketplace. Valued uses two of these: e-mail first, the interface second.

Step one: DATEV Upload Mail

With DATEV Upload Mail, the mandate in DATEV Unternehmen online receives an e-mail address of its own. Every document sent as an attachment to that address lands among the documents of the tax adviser. DATEV built the feature so that invoices received by e-mail can be forwarded with one click, without saving them in a folder first; paper documents can be photographed or scanned and sent the same way.

DATEV describes the activation as a single step in the program, free of charge. After that, the documents are available to the firm for bookkeeping at once.

For the Valued connection this means: once the mandate has its Upload Mail address, Valued can send documents to it. The address is specific to the mandate, so documents for your private return and for your GmbH go to different addresses if the firm keeps two mandates. Ask the firm for the address of each mandate, and make sure you know which entity each address belongs to before anything is sent.

The e-mail route has the advantage of needing nothing from the firm beyond activation. Its limit is that of e-mail itself: a message is sent, and what happens to it on the other side is not reported back to the sender in a structured way.

Step two: the DATEV interface

The second step uses DATEVconnect online for document images, an interface DATEV lists as accounting:documents. It is a REST interface reachable over the internet; sign-in runs through OAuth 2.0 with OpenID Connect. DATEV publishes its user information and the conditions of use under its connectonline pages.

Compared with e-mail, a direct interface changes three things. No mailbox sits between the sender and the firm. The document is addressed to a mandate through an authorised connection rather than to an e-mail address that anyone could write to. And each call receives an answer from the receiving system, so that a failed delivery shows up as a failure instead of as silence.

The e-mail route comes first because it works with any mandate that has Upload Mail switched on. The interface follows as the second step.

The log

Valued logs every transmission. That sounds like a detail and is the part you will be glad of a year later.

When the firm asks in May whether the capital call from last October was sent, the answer should not depend on searching an outbox. A transmission record lets you answer what was sent, when, to which mandate and with what result, and resend a single document if needed.

The log also sits alongside the duty to keep records. The Bundesrat approved the Fourth Bureaucracy Relief Act (BEG IV) on 18 October 2024, two years ago today. Since 2025, booking documents such as invoices, receipts and bank statements have to be kept for eight years instead of ten. Annual accounts, books and inventories remain at ten years, commercial and business letters at six. Where those duties apply, for instance in the books of a GmbH, a record of what was handed to the adviser and when is a useful addition to the documents themselves, both for the firm's questions and for a tax audit. It does not replace keeping the documents.

What the connection does not do

It moves documents. It does not assess them.

Whether a distribution is a return of capital or income, how a fund's tax figures are to be treated, which year a payment belongs to: that judgement stays with your tax adviser, as it should. Valued makes sure the documents arrive complete and on a traceable path. It does not give tax advice, and a document in the firm's inbox is not a booking.

Nor does the connection fix what is wrong in a document. A quarterly report with an error is transmitted with the error. If you want to know which figures in such a report deserve a second look, we described that in how to read a quarterly fund report. For depots, the annual bank statement has its own logic, explained in reading the bank statement per depot.

Before you talk to your firm

The connection works best when the firm knows it is coming. Points to settle:

• Does the firm use DATEV Unternehmen online for your mandate, and is DATEV Upload Mail activated for it.
• How many mandates there are, for example one private and one for a GmbH, and which Upload Mail address belongs to which.
• Which kinds of document the firm wants to receive by this route, and which it already gets elsewhere, so that nothing arrives twice.
• Who at the firm watches the incoming documents, and how they will let you know if something is missing.
• When the firm would like to move from e-mail to the interface, once it is available for your mandate.

To see the steps before you do them with real documents, open the public demo and look at the DATEV connection there. The other connections Valued offers are listed under integrations, and how data is protected is described on our security page.