E-Invoicing 2027/2028: Why Receiving Is the Bigger Challenge

All the attention is currently focused on the question: “When do I have to start sending e-invoices?”. This is understandable – and misleading. Because sending them is the technically simpler part. The real, costly and underestimated problem lies on the receiving side and in the archive.

The obligation to receive e-invoices has been in force since 1 January 2025 – for all businesses, without exception. Most businesses currently ‘comply’ by saving structured XML invoices as files in their email inboxes whilst continuing to refer to the accompanying PDF. This is dangerously close to ‘non-compliance’. Anyone who sends invoices correctly in 2027 but continues to handle their incoming invoices in this way has failed to meet the requirement.

This article summarises the deadlines briefly and accurately, explains the formats without technical jargon – and then focuses on the part that hardly anyone talks about, because it is not a tax issue but a procedural one.

Part 1: The deadlines – brief and accurate

From 1 January 2025: Obligation to receive e-invoices for all. Every domestic company must be able to receive and process e-invoices – with no transition period and no exceptions.

Until 31 December 2026: A transition period still applies to sending: paper invoices are still permitted; other formats (PDF) are only permitted with the consent of the recipient company.

From 1 January 2027: Obligation to send e-invoices for companies with a turnover in the previous year (2026) exceeding €800,000. They must send all domestic B2B invoices as e-invoices.

Until 31 December 2027: Businesses with a turnover in the previous year of ≤ €800,000 may still send paper or PDF invoices (with consent).

From 1 January 2028: Mandatory electronic invoicing for all – regardless of turnover.

Exceptions: Small-value invoices up to €250 gross, travel tickets, services provided by small businesses under Section 19 of the German Value Added Tax Act (UStG) and B2C invoices.

Important for self-assessment: The total turnover of the previous year is the decisive factor. Anyone with a turnover exceeding €800,000 in 2026 will be subject to the electronic invoicing requirement from 1 January 2027 – not just from 2028. And this threshold is lower than it sounds: even a craft business with just a handful of employees can reach a turnover of €800,000. The 2027 threshold affects small and medium-sized enterprises across the board, not just large corporations.

Another change that hardly anyone has noticed: The legislator has reduced the retention period for accounting documents – and thus for invoices – from ten to eight years with effect from 1 January 2025. It sounds like a relief. In practice, however, it means that your archive must now manage retention periods differently, as other documents are subject to longer retention periods. An archive that simply applies a blanket rule of ‘ten years for everything’ is therefore no longer compliant, but merely convenient.

Part 2: A five-minute guide to formats – XRechnung, ZUGFeRD and the ‘original’ trap

An e-invoice as defined by the law complies with the EU standard EN 16931. In German practice, you’ll come across two formats:

XRechnung is a pure XML format – a structured data record without a human-readable view. To humans, an XRechnung looks like source code. It is the standard for public sector contracting authorities and is becoming increasingly widespread in B2B business.[DH1]

ZUGFeRD 2.x is a hybrid format: a PDF file in which the structured XML data record is embedded. When you open the invoice, you see a standard PDF – the system reads the XML. It is precisely this convenience that is the pitfall.

This is where the misunderstanding arises that will prove costly later on: A standard PDF – without embedded XML – is not an e-invoice. Not even if it arrives ‘electronically’ via email. And with ZUGFeRD, the following applies: the authoritative, legally binding part is the structured data record, not the visual display. Anyone who processes only the PDF view of a ZUGFeRD invoice and ignores the embedded XML is processing the invoice without taking the legally relevant content into account.

And EDI? Established EDI procedures remain permissible – even beyond 2028 – provided that a legally compliant reporting data set can be extracted correctly and in full from the EDI data set. So if you currently use EDI with major trading partners, you do not need to make any changes – but do check whether your procedure allows for this extraction.

Part 3: Why ‘we can receive e-invoices’ is usually not true

The obligation to receive e-invoices sounds like a problem that’s been solved – ‘after all, the invoice does arrive’. But the law demands more than just arrival. An e-invoice is a structured data record. Receiving it correctly means: reading out the structured content, processing it and archiving the structured original in an audit-proof manner.

In the reality faced by many companies, however, the following happens instead:

• The XML or ZUGFeRD file ends up as an attachment in the ‘rechnungen@’ collective inbox.
• A person opens the accompanying PDF (in the case of ZUGFeRD) or a viewer and manually enters the values.
• If anything is archived at all, it is the PDF, not the structured data record.

This is a problem for four reasons:

1. Archiving fails to capture the original. It is the structured format that is authoritative and subject to retention requirements, not the human-readable representation. Anyone who archives only the PDF image has, in case of doubt, not retained the original. This is a matter covered by the GoBD – the principles for the proper maintenance and retention of books, records and documents in electronic form – not a matter of convenience.

2. The input VAT risk. Input VAT deduction requires a valid invoice. Where e-invoicing is mandatory, a mere PDF no longer meets this requirement. Anyone who fails to clearly distinguish at the point of receipt what constitutes a valid e-invoice – and cannot retain the original – risks disputes over input VAT deduction in the event of an audit. This is not a theoretical quibble, but hard cash.

3. Manual data conversion erodes precisely the efficiency that e-invoicing was intended to deliver. The very purpose of structured data is automated processing – verification, account allocation, approval and posting. Anyone who simply retypes the data has fulfilled their obligation but squandered the benefit. And this is a permanent issue: every single invoice, every month, with an error rate.

4. No end-to-end, auditable workflow. Incoming invoices via email lack audit-proof allocation, a traceable approval chain and automatic deadlines. In the event of an audit, ‘was sitting in the inbox’ is not a reliable document trail.

A real-world scenario

A medium-sized engineering firm, 240 employees, around 1,400 incoming invoices per month. On paper, the company is ‘e-invoice-ready’: the ERP system can generate XRechnungen, preparations for sending e-invoices in 2027 are in place, and the tax advisers are satisfied.

The reality is quite different. Invoices arrive via three channels: a central inbox, a supplier portal and – for two major customers – EDI. Everything gets mixed up in the central inbox: standard PDFs, ZUGFeRD files and pure XRechnungen. The accounts team prints out what they can read, types up what the ERP system doesn’t automatically import, and archives the emails ‘just in case’ in the mailbox archive.

What happens here without anyone realising it is that nobody can read the XRechnungen without a viewer, so they are left lying around until someone asks for them – and discount periods slip by. Nobody ever reads the ZUGFeRD XML files; it is the visual representation that is processed and archived. And the email archive is neither immutable nor organised by document type. Three channels, three formats, no standardised process – and, formally speaking, the company has been obliged to accept these documents since 2025.

The punchline: this company has invested in outbound processes, where the obligation only comes into force in 2027 – whilst ignoring the inbound side, where the obligation has long been in force and money is being left on the table every day. This is not a contrived extreme case. This is the norm.[DH2]

Part 4: What proper e-invoice processing actually needs to achieve

Anyone who wants to comply with the obligation and reap the benefits needs an end-to-end workflow from receipt to archiving. The key building blocks:

A central inbox rather than a proliferation of mailboxes. All channels – email, portals, EDI – feed into a structured inbox that automatically recognises XRechnung and ZUGFeRD, extracts the structured data record and validates it. Not a person manually transcribing a PDF.

Validation against the standard. The system checks incoming e-invoices against EN 16931. Detecting formally incorrect invoices at an early stage saves correction loops – and safeguards input tax deduction before the invoice even enters the accounting system.

Audit-proof archiving of the original. The structured format is archived in an unalterable and GoBD-compliant manner; the system logs every edit, and the entire lifecycle remains traceable – including the differentiated retention periods (eight years for supporting documents, different periods for other records).

Workflow with approval and account allocation. Verification, substantive and arithmetic approval, suggested account allocation, transfer to the ERP system – as a traceable, automatable chain rather than an email ping-pong game. A side effect: cash discounts become predictable again because processing times become measurable.

Integration rather than silos. E-invoice processing is not an additional tool alongside the ERP system, but the inbound process that feeds seamlessly into existing financial and document systems.

This is where a well-thought-out document management system comes out on top compared to a mere ‘e-invoice dispatch function’. After all, almost any tool can send invoices. Processing incoming invoices cleanly, in a way that stands up to audit scrutiny, and automatically – that is the real task.

Part 5: The roadmap – working backwards

If you are required to send e-invoices from 1 January 2027 (2026 turnover exceeding €800,000), don’t think from the deadline onwards, but work backwards:

Now until the end of 2026 – stock-taking and the incoming side. Which invoicing channels exist? Which formats are currently received, and what happens to them? Does the structured original end up in the archive – or the viewable copy? These questions cost little and determine everything that follows. The incoming side has been mandatory since 2025 anyway; tackling it first is not an optional extra, but rather catching up with an existing requirement.

In parallel: system selection and integration. Whether you upgrade your existing document management system, activate an ERP module or set up a new inbound processing system – the decision requires specifications (see Part 4), not product brochures. Realistically, you’ll need several months for selection, integration and testing, depending on your system landscape and channels.

By mid-2026 at the latest: Test dispatch. Standards-compliant generation, transmission channels, special cases (credit notes, advance payments, recurring invoices). Anyone who only starts testing in December 2026 will be testing in live operation.

From 2027: Don’t just aim to be finished; measure performance. Throughput times, automation rate, error rate. E-invoicing is not a project with an end date, but a process that is intended to pay off.

And looking ahead: at EU level, ViDA (“VAT in the Digital Age”) has already established that structured electronic invoices and digital reporting obligations for cross-border B2B transactions are on the way – the timeframe extends into the 2030s. At national level, too, e-invoicing is designed as a precursor to a transaction-based reporting system. Anyone who currently implements only the legal minimum will have to rebuild their system in a few years’ time. Anyone who sets up the process properly from the outset will be able to integrate the reporting functionality later as an extension, rather than a completely new build.

What you should check now

Regardless of whether you become subject to the sending obligation in 2027 or 2028 – the receiving side is already mandatory today. Three questions you should answer honestly:

1. Do we archive the structured original – or just the PDF? If the answer is ‘PDF’ or ‘don’t know’, there is an urgent need for action, regardless of 2027.

2. Do we process incoming invoices automatically – or does someone key them in manually? This is the key factor that allows e-invoicing to save money rather than merely fulfilling a legal obligation.

3. Is our outgoing invoicing system ready for 2027/2028 – and do we know which tier we fall into? The previous year’s turnover for 2026 is the deciding factor. Those with turnover just over €800,000 have less time than they might think.

The obligation to issue e-invoices has a clear deadline and is technically manageable. The incoming and archiving side has no specific deadline – it has long been in force – and is precisely for this reason the greater unresolved risk.

Why choose adesso for e-invoicing

adesso supports companies throughout the entire e-invoicing transition – from structured invoice receipt through validation and approval workflows to GoBD-compliant archiving of the structured original and integration into the ERP system. adesso is one of Germany’s largest IT service providers – and, according to the Lünendonk list, the largest IT service provider in Germany: over 11,300 employees, more than 65 locations in Germany and Europe, and a turnover of 1.47 billion euros in the 2025 financial year.

For your project, this means that at adesso, e-invoicing doesn’t stop at the system boundary. Whether it’s SAP processes, ERP integration, cloud operations or AI-supported document processing – all the necessary expertise is under one roof, from document management to outstanding SAP expertise. One project partner instead of a chain of service providers.

Just how audit-proof is your invoicing process today? Our free e-invoicing readiness check guides you through receipt, processing, archiving and dispatch in just a few minutes – and highlights where your gaps lie.