How and why to integrate DATEV Unternehmen Online (DUO) with a spend management platform

Imagine it’s the last week of the month. Your top salesperson is rushing to catch a flight, your tax advisor is asking why three receipts are missing again, and your finance team is still fixing exports instead of reviewing numbers. Nothing is fundamentally broken — but small gaps have accumulated, and month-end feels more stressful and fragmented than it should.

For many CFOs, these issues surface in DATEV Unternehmen Online (DUO). Missing documents, inconsistent coding, and late clarifications all show up there, making it seem like DATEV is where the process slows down. In reality, DUO is simply where upstream inconsistencies become visible.

That’s why improving month-end doesn’t start inside DATEV itself. The real leverage lies in how spend, receipts, and approvals are handled before accounting begins — long before any export or handover takes place. Once that foundation is in place, DATEV DUO becomes exactly what it’s meant to be: a reliable environment for review, posting, and collaboration with tax advisors.

1. Why DATEV DUO needs a modern spend management integration

For mid-sized finance teams processing hundreds or even thousands of transactions each month, DATEV Unternehmen Online (DUO) is the backbone of statutory accounting - especially in Germany and Austria. It is where tax advisors expect clean, compliant data — and where month-end accuracy ultimately lives.

However, DATEV DUO is only as strong as the data it receives. In many organisations, spend, receipts, and approvals still happen upstream in fragmented ways. Card transactions sit in one system, invoices in another, receipts are chased by email, and approvals are handled manually. As a result, by the time data reaches DATEV DUO, finance teams are often forced to correct, complete, or re-upload information that should have been captured correctly at the source.
The effectiveness of DATEV DUO therefore depends on receiving complete, structured, and correctly coded data from the start. This includes:

• Transaction details
• VAT information
• Cost centres and account assignments
• Supporting documents, correctly linked and ready for audit

All this delivered in a single, consistent flow.

This is where a modern spend management platform plays a critical role. By bringing payments, receipt capture, approval workflows, and preparatory accounting together in one system, it closes the gap between day-to-day spending and statutory accounting. Instead of fixing data just before export, finance teams can ensure expenses are accurate, compliant, and audit-ready long before they reach DATEV DUO — laying the foundation for faster closes, fewer errors, and smoother collaboration with tax advisors.

2. The problem: manual data and document transfer slows everyone down

When spend, receipts, and invoices are handled across disconnected tools and channels, exporting data to DATEV DUO often becomes one of the most time-consuming parts of the month-end process. Instead of reviewing figures and closing the books, finance teams find themselves caught up in administrative work that should already be done.

Receipts and invoices arrive in many different formats and locations — AP inboxes, personal email accounts, forwarded messages, paper documents, or screenshots. Without automated capture, finance teams effectively become internal “hunter-gatherers”, spending significant time identifying what is missing, tracking down documents, and ensuring that each transaction is supported by the correct attachment. This effort is rarely visible, but it adds up quickly.

Once documents are collected, the next challenge begins. Transaction data often needs to be corrected, completed, or rekeyed before it can be exported. Cost centres, VAT rates, accounts, and IBANs must be checked manually, increasing the likelihood of errors. Errors such as incorrect IBANs, duplicate uploads, or missing invoices prevent automatic reconciliation and increase compliance risk, weakening the reliability of the data being handed over to DATEV DUO.

The impact becomes even more apparent when external tax advisors are involved. Instead of working with clean, structured data, advisors are forced into clarification loops, requesting missing information or questioning inconsistencies. Collaboration turns reactive, with multiple back-and-forths that delay progress on both sides.

As transaction volumes grow, these manual steps don’t simply take longer — they become harder to control. More people touch the process, exceptions multiply, and small inaccuracies turn into recurring month-end issues. The result is a delayed close, reduced confidence in data quality among controllers, and tax advisors spending valuable time fixing problems rather than reviewing and advising.

3. What a good integration with DATEV DUO should offer

A good integration with DATEV DUO should make accounting work easier — not add another layer of complexity. Instead of simply transferring data at the end of the month, it should support finance teams throughout their daily workflows and reduce the amount of manual preparation needed before anything reaches DATEV.

One key requirement is flexibility. Finance teams need to decide what data is exported to DATEV DUO based on their accounting setup. In some cases, that means exporting full expense transactions. In others, only IBANs are required for invoices paid outside the spend management platform. A reliable integration supports both scenarios — and combinations of them — without forcing teams into a one-size-fits-all process.

Beyond flexibility, a strong DATEV DUO integration should ensure that the following core requirements are met:

• Seamless transfer of receipts and invoices together with transaction data, so documents appear directly in DATEV Belege Online alongside the booking entry
• Early capture of KOST1, KOST2, and BU keys (0, 7, 8, 9) before data reaches DATEV, instead of fixing entries after export.
• A clear audit trail your tax advisor can tap into, with each transaction, document, and booking entry clearly linked.

When these elements are in place, finance teams benefit from cleaner data, faster reviews, and fewer follow-up questions. Supporting documents are always available where tax advisors expect them, coding is consistent from the start, and the entire accounting process becomes more transparent, compliant, and reliable.

4. How the integration works in practice

Imagine you’re a CFO in a mid-market company looking to integrate DATEV DUO into your existing finance setup. At this stage, you’re not interested in technical feature lists — you want to understand how the integration works day to day, how it affects your team’s workload, and what will change in the month-end routine.

In a typical workflow, an expense or payment is made through the spend management platform. At the moment of purchase or submission, the receipt or invoice is captured immediately, while the details are still clear and easy to verify. This removes the need for finance teams to chase documents later and ensures that each transaction is supported from the start.

Next, the expense is coded using predefined rules for KOST1, KOST2, and BU keys (0, 7, 8, 9). Because this information is applied early, the data is already structured and aligned with DATEV before it ever leaves the system, with no rework needed to make it export-ready.

Once the transaction has been reviewed and marked as ready, fully reconciled data and documents are transferred automatically to DATEV DUO as part of the full export. In DATEV, entries appear together with their receipts or invoices, so your tax advisor can work with complete, consistent records without follow-up questions.

For a CFO, the key benefit is that this process runs continuously throughout the month, rather than concentrating effort at month-end. Manual handovers are reduced, visibility improves, and the integration becomes a natural part of everyday finance operations, not an extra task when deadlines are tight.

5. Specific benefits of integrating Payhawk with DATEV DUO

Integrating Payhawk with DATEV DUO is designed to remove friction from everyday accounting work, especially in environments with growing transaction volumes and multiple spend types. The benefits are practical and operational, focusing on reducing manual effort while improving consistency and control.

In practice, the integration supports finance teams across several key areas:

• Flexible exports allow teams to export all expenses for automatic reconciliation, or—when paying externally—export only IBANs via CSV, or toggle between approaches depending on the expense type.
• Automated transfer of transaction data together with supporting receipts or invoices, ensuring documents appear in DATEV DUO alongside the relevant booking entries
• Elimination of CSV files and manual uploads through DATEV-compatible formats with correct fields and mappings applied from the start
• Efficient handling of recurring spend, where payments are categorised and documented once and then processed consistently in every cycle

This flexibility allows teams to maintain their existing accounting logic while still benefiting from automation. Data is handed over in a structured, DATEV-ready format, reducing preparation effort and structural errors before export.

As a result, finance teams spend less time fixing issues and chasing receipts, and more time reviewing and closing. By standardising data before it reaches DATEV DUO, teams typically reduce manual corrections and follow-ups — improving both efficiency and confidence in the numbers.

6. What this integration does — and doesn’t — replace

It’s important to be clear about the role of a DATEV DUO integration and what problems it is designed to solve. A strong integration supports finance teams by removing unnecessary manual work, but it does not replace professional judgment or core accounting responsibilities.

What the integration does is reduce the amount of preparation required before data reaches DATEV DUO. By capturing documents and structuring data earlier in the process, finance teams spend less time cleaning up exports and correcting errors. This leads to higher data quality and greater consistency across transactions. It also simplifies collaboration with external tax advisors, who receive complete, well-prepared entries and can focus on review and advisory work instead of follow-up questions.

At the same time, the integration does not replace DATEV DUO as the accounting system of record. DATEV remains the central environment for statutory accounting and final postings. The integration also does not remove the need for accounting review or approval, nor does it automate booking logic decisions that require professional expertise or interpretation.

Being explicit about these boundaries matters. It helps set realistic expectations and build trust with CFOs and controllers, ensuring the integration is seen as a reliable support tool — not a shortcut that compromises accounting control.

7. Real outcomes for finance teams

When spend-data and documents are structured before they reach DATEV DUO, the impact is felt across the entire finance function. Instead of reacting to issues at month-end, teams gain a process that supports accuracy and control throughout the month.

Finance teams spend significantly less time chasing receipts, filling in missing information, or correcting exports before they can be handed over. Because data and documents move together and are coded early, duplicate work across tools is reduced, and manual rework becomes the exception rather than the rule.

A central repository for all spend data and documents, with the flexibility to pay each expense the way it makes most sense. As a result, collaboration with tax advisors becomes noticeably smoother. Advisors receive complete, consistent entries in DATEV DUO and can focus on reviewing and advising instead of requesting clarifications or additional documents. Clear export status and traceability help both sides quickly understand what has been transferred and when.

At the same time, audit readiness improves naturally. With a transparent link between expenses, payments, documents, and their export history, finance teams are better prepared for audits — without having to introduce extra checks or processes on top of their day-to-day work.

8. Getting started with the integration

Getting started with a DATEV DUO integration doesn’t require a large IT project, but it does benefit from a clear setup and a few upfront decisions. For mid-market finance teams, the goal is to configure the integration once — and then let it run reliably in the background.

In practice, the setup typically involves the following steps:

• Export full transactions, IBANs only, or both — on an ad-hoc basis, whether for automatic reconciliation, external payments, or a combination of both.
• Configuring approval workflows and assigning KOST1 and KOST2 (for example, location and department, or department and project), including defining when an expense is considered “ready” for export and ensuring these dimensions are applied consistently.
• Ensuring the right permissions are in place in DATEV DUO and that tax advisors have enabled the required access so data can flow without interruptions
• Enabling automatic or scheduled exports so expenses and payments are transferred only after review and approval
• Monitoring export results and refining rules over time using export statuses and logs

Once the structure is set, the integration runs as a continuous process rather than a one-off task. Reviewed and approved data is handed over to DATEV DUO at a clear point in the workflow, reducing the risk of incomplete information and minimising corrections after export. Over time, visibility into sync results helps finance teams spot exceptions early, fine-tune their setup, and keep accounting operations running smoothly. Book a demo to see how this works in practice and how you can run DATEV integrations with finance-grade controls from day one.

9. FAQs about DATEV DUO integration

• Can I choose what data to export to DATEV DUO?

• You can control what gets exported and when, based on whether you choose to export full transactions or a combination. Full transactions include the expense together with its associated payment and documents, exported once the expense is checked/reviewed and the payment is settled. A combination allows you to export expenses for accounting and reconciliation, while exporting payments (or IBANs) separately once they are cleared — for example, when payments are handled externally. In Payhawk, you have visibility and control through export filters and export status, making it easy to manage what’s included in each handover and to troubleshoot exceptions.

• Are attachments sent together with the data?

• Yes — supporting documents are exported so that entries in DUO have the relevant receipt/invoice available. One important detail from the help content: the expense document is attached to the expense booking (and the expense and payment bookings are linked via the document reference number). That’s why you still get a complete record in DUO without needing separate document uploads.

• Do I still need to manually enter anything in DATEV?

• The integration reduces manual entry because reviewed expenses and settled payments are exported automatically. However, it doesn’t replace accounting control: finance teams still review/correct data in Payhawk before export, and tax advisors retain responsibility for booking logic and final posting decisions in DATEV. Also, the help content is explicit that changes made after export won’t update the already-exported version in DUO — if you re-review and export again, a new entry is created rather than updating the original.

• What if I work with an external tax advisor?

• That’s the most common setup — but there are prerequisites. Before you begin, your tax advisor needs to enable the MyDATEV client for “Rechnungsdatenservice 1.0” and grant you the necessary admin rights. In DUO, specific permissions/settings for document handling must be configured (the help article describes changing the editing form and selecting the appropriate folders). Once this is set up, your advisor can access structured entries in DUO with significantly fewer follow-up questions.