Between your bookkeeping and your German tax firm there are three routes, and they differ less in technology than in the question of who sets them up. The first is DATEV Unternehmen online: a shared platform in the DATEV data centre where you file your receipts and, as DATEV describes it, access the same data as your tax advisers. The second is the DATEV data services, interfaces through which your own accounting software automatically sends receipt data, receipt images or finished journal entries into the DATEV world. The third is a file in the DATEV format, a booking batch your firm imports into its accounting program. The first two are usually ordered and enabled by the firm, not by you: the data services run through MyDATEV Mandantenregistrierung according to the price list, and assigning rights for Unternehmen online requires a firm-held SmartCard with administration rights according to DATEV's guide for tax firms. Price-wise this starts at 11.56 euros per month for DATEV Unternehmen online plus 3.83 euros per client record for DATEV Belege online, each net of VAT (DATEV price list for companies, as of 08/2026). That is the entry point, not a total price: data services are tiered by volume, and under the Leistungsverbund model your firm bills you. The third route does not appear in that price list at all, because it is only a file.
What interests me most is what happens before it. Whether a receipt is captured completely and sorted correctly is decided before an interface passes it on. That preparatory work runs automatically in my business, sign-off and the tax return stay with people. What that setup looks like is under Hiring AI employees and in AI Agent for Bookkeeping and Inbox. This post describes the market and not my own configuration, and it is not tax advice: which route fits your bookkeeping is something you decide with your firm.
The three routes at a glance
Route 1: DATEV Unternehmen online
This is the connection most people mean when they say "DATEV". Receipts arrive three ways: as a photo through the DATEV Upload mobil app, by scanner and drag-and-drop, or forwarded to DATEV Upload Mail. With the mail route, agree who forwards what; misaddressed mails and duplicates otherwise surface only at the firm. Which other apps come into question is in Receipt Scanning Apps: The Best Tools.
What matters for the cost section is what the contract includes and what costs extra. According to the price list, DATEV Stammdaten online, Bank online, Kassenbuch online and Auswertungen Rechnungswesen online are included; Belege online, Auftragswesen next, Belegfreigabe online and Liquiditätsmonitor online require Unternehmen online and are billed on top. If all you want is a digital cash book, the smaller version is in Cash Book Apps Compared.
For access you need an access medium: DATEV SmartLogin, DATEV mIDentity or a DATEV SmartCard. SmartLogin is free according to the price list when ordered for use in the company, but still has to be ordered; the mIDentity stick with SmartCard is listed at 50.00 euros one-off. One detail from that guide causes trouble in practice: the registration letter for SmartLogin is valid for twelve weeks from issue, after which the firm has to renew the code through the SmartLogin administration.
The same guide names a recommendation that has nothing to do with technology. Because of the ten-day rule in the GoBD, DATEV recommends uploading incoming receipts within ten days so they are filed in good order. That is a manufacturer's recommendation on how to comply, not a deadline anyone can read out to you as law. What the actual obligations are is in Bookkeeping Basics for the Self-Employed.
Route 2: The data services, when your software is already running
If you already work with other accounting or inventory software, you do not have to move. DATEV offers a family of cloud services for that; the four that matter for small businesses differ in what they transport; for PayPal, Stripe and shops there are separate payment data services on top, explained in Connect DATEV to PayPal, Stripe and Shopify.
- DATEV Rechnungsdatenservice 1.0 transfers structured receipt data and receipt images into DATEV Belege online and the online cash book, where they become booking proposals for the accounting programs. This is the route when the firm does the bookkeeping and you only supply receipts.
- DATEV Buchungsdatenservice transfers finished entries. DATEV lists, among others, postings and recurring postings, posting text constants, account notes, text keys, payment terms, debtor and creditor master data, and journal entries for fixed asset accounting. This is the route when you post yourself.
- DATEV Belegbilderservice Rechnungswesen moves the receipt images and appears in the price list at 0.00 euros one-off. It requires a contract for DATEV Unternehmen online.
- DATEV Bankdatenservice handles account transactions and payment orders. The price of 1.37 euros per month applies per bank connection, according to the price list, for providing and archiving account transactions and for payment orders in the DATEV data centre.
If the firm needs both the receipts and the booking batch, two services run side by side, depending on your software the Buchungsdatenservice and the Belegbilderservice, for example. DATEV describes the setup in three steps: order the data service through an assistant, create the record in DATEV Unternehmen online, set up the access rights. Whether your software plays along is visible in DATEV's directory of interface providers; DATEV notes that its own interface specifications govern their review and release. What such a connection looks like in the accounting tool itself is shown in Lexoffice Integration: The Main Routes.
Route 3: The file in DATEV format
The underrated route. The common accounting tools for small businesses export a booking batch in the DATEV format, and for many firms that is enough; which those are and what they cost is in Accounting Software for Small Businesses. DATEV publishes the functional scope of this interface per provider. From that you can read what such a file consists of: booking batches for purchasing, cash and sales, plus master data with the account as a mandatory field. For the transaction data, amount, debit-credit indicator, account, contra account and document date are mandatory; optional fields include document field 1 and 2, posting text, discount and the lock flag.
The drawback compared with the data services is the manual work: somebody exports, somebody sends, somebody imports. The advantage is that you need neither a DATEV contract nor an access medium, and no cloud service has to be cancelled and re-ordered when you change firms. The change itself is still work: the new firm reconciles the chart of accounts, number ranges, lock status and import parameters. Send them a test export beforehand and have them confirm the import. If you would rather not work that through alone, bring the sequence into the community.
Why your tax firm has a say in the decision
The DATEV connection is rarely a purely technical decision: the record belongs in the firm's numbering system. DATEV's commissioning guide, version dated 17 October 2024, states that the record in Unternehmen online has to be created under the same adviser and client number under which the firm keeps that client in its accounting program.
Three things follow, useful before you talk to your tax adviser.
First, as a rule the firm does the setting up. The guide is addressed to tax firms and describes commissioning as their task: order the contract, administer the client's rights, create the client in DATEV Unternehmen online, then commissioning at the client's end. The first assignment of rights there requires a firm-held SmartCard carrying administration rights. That does not lock you into this route: according to DATEV, data services can also be ordered through MyDATEV Mandantenregistrierung, and in Rechteverwaltung online a client can be granted administrator rights for their own location. What applies to you depends on the contract model and on existing contracts.
Second, the invoice often lands there too. In the normal case, which DATEV calls Leistungsverbund, the costs for Unternehmen online and Belege online appear on the firm's invoice. Only in the membership-bound client model does DATEV invoice the company directly. What you pay is then a question of your agreement, not of the price list. The guide explicitly names a written processing agreement for it.
Third, access is a question of rights, and the record is the unit behind them. In DATEV, people and groups are enabled for cloud applications through Rechteverwaltung online; what someone sees depends on the rights assigned. Have them show which rights sit on your record. With other vendors there is no such leeway: at Lexware Office the tax firm's access cannot be restricted to individual areas, according to the vendor, and the firm sees all information including every connected bank account. Either way, connecting to a firm is a deliberate release to a contractual partner. What data you hand to outside systems in general is covered in AI and Privacy: What the AI Gets to See.
Four questions get the conversation to the point. Do you work with DATEV, and if so, do you post or do I? Is a booking batch as a file enough for you, or do you want a data service? Who orders the contract and the access medium, and on whose invoice does it run? What happens to the record if we end the arrangement?
What the connection costs
All the following prices come from the DATEV price list for companies, as of 08/2026, in euros and net of VAT.
Two lines deserve a second look. For Belege online, billing starts when the record is created, regardless of whether any receipt arrives, and for the Buchungsdatenservice the base price of 1.36 euros applies from the creation of a client record regardless of any data transfer. A connection that is set up but unused still costs money. The 350.00 euros in the last line is, according to the price list, the flat fee for an inactive Unternehmen online mandate; it requires a cancelled contract and a membership in DATEV eG for the period of storage. What it covers and for how long is in the product sheet.
What an AI employee does at this point
A connection transports. It does not check. That gap is exactly where Peter, my AI employee for receipts and bookkeeping, sits. He does not work on an interface but in my accounting interface in the browser: he reviews the incoming receipts, assigns the right receipt type to each one, matches the credit card statement against them line by line and reports what does not fit. He follows a written process description; what is not in it, he does not do.
Three rules are hard-wired into him. He clicks nothing on suspicion: every state-changing action is covered by a step in an approved process. Amounts, dates and document numbers always come from the screen, never from memory; if something does not match exactly, he reports it as open instead of making it fit. And he does not post: his process knows sorting and matching, sign-off stays with me and my tax adviser. When a bulk download action once triggered an e-mail delivery, he stopped immediately, logged the incident and told me, even though no receipt had been changed.
How that browser work runs technically is in Claude in Chrome: How to Use the Extension. What today's tools can do on their own when reading and coding receipts is sorted in AI Bookkeeping: What Actually Works Today.
Frequently asked questions
Who sets up the DATEV connection, me or my tax adviser?
Usually the firm, though that is not technically mandatory. DATEV's guide is addressed to tax firms and describes ordering the contract, administering rights and creating the client as their tasks; assigning rights there requires a firm-held SmartCard with administration rights. Data services also run through MyDATEV Mandantenregistrierung. Your job is the commissioning on your own side.
What does the DATEV connection cost?
Entry is 11.56 euros per month for DATEV Unternehmen online plus 3.83 euros per client record for DATEV Belege online, net of VAT (as of 08/2026). Data services come on top depending on volume, starting at 1.36 euros per month for the Buchungsdatenservice. That is not a total price for every constellation; the tiers depend on volumes and records.
Do I need DATEV if my software already has a DATEV export?
Not necessarily. A booking batch in DATEV format is a file your firm can import without you holding a DATEV contract. Whether a data service pays off depends on your receipt volume and on who does the posting.
What is the difference between Rechnungsdatenservice 1.0 and Buchungsdatenservice?
Rechnungsdatenservice 1.0 transfers receipt data and receipt images into DATEV Belege online, where booking proposals are generated from them. The Buchungsdatenservice transfers finished postings including master data into the accounting programs. In short: delivering receipts versus delivering entries.
Can I limit what my tax firm sees?
That is decided by the rights assigned. In DATEV, people and groups are enabled through Rechteverwaltung online, so ask who holds which rights on your record. With other vendors there is no such leeway: Lexware writes itself that the tax adviser login cannot be restricted to individual areas. Plan the connection as a deliberate release to a contractual partner, and put the arrangement in writing.
How to take this further
Do not start with the technology, start with a phone call: ask your firm the four questions above and write the answers down. That usually settles it: if the firm posts and you only supply receipts, Unternehmen online with Belege online or a Rechnungsdatenservice is enough; if you post yourself, the question is the Buchungsdatenservice or an export file. Only then is it worth opening the price list.
If your receipt volume reaches the point where manual work stops being fun, the connection is not the answer, the preparation before it is. How to hand that preparation to an AI employee without handing over control is what I walk through step by step in my community Claude Practitioners.
