A guide to e-invoicing for accounts payable teams

Many finance teams that receive invoices by email treat that workflow as e-invoicing. If the team still opens each file, reviews it, and keys the data into the accounting system, the process is manual even though the invoice arrived digitally. Many AP software vendors use "e-invoicing" loosely, and buyers can end up with platforms that still require manual work at intake.

This guide from Brex covers what e-invoicing is, where it fits within the AP stack, the formats and networks involved, and how to run it when suppliers send structured and unstructured invoices. It also covers e-invoicing mandates already in force in parts of Europe and explains why U.S. companies need to assess whether their local operations and transactions fall within scope.

The aim is to give AP teams enough grounding to evaluate vendors accurately and recognize when "e-invoicing ready" describes a PDF workflow. Consider this guidance along with input from your professional advisor when making business decisions.

Key takeaways

Many platforms marketed as e-invoicing may still run a PDF workflow, and knowing the difference can help buyers avoid paying for the label alone.
E-invoicing mandates in Belgium, Germany, France, and Poland are being phased in. Requirements for U.S. companies depend on their local establishment, VAT status, and transactions; selling into these markets does not automatically trigger an obligation.
Many companies are likely to run a mix of structured and unstructured invoices during a transition, and an e-invoicing rollout can plan for that instead of an all-or-nothing switch.

What is e-invoicing?

E-invoicing is the issuance, transmission, and receipt of invoices in a structured digital format that supports automatic electronic processing. In a B2B workflow, this allows the buyer’s accounting software to read invoice data without manual re-keying, provided the software supports the format. Common formats include XML-based UBL (Universal Business Language) and CII (Cross-Industry Invoice), as well as EDI invoice messages such as EDIFACT. Whether a particular format satisfies a legal mandate depends on the applicable requirements.

Ordinary PDFs without structured invoice data, Word documents, spreadsheet invoices, and scanned paper invoices typically require extraction or mapping before processing. Hybrid formats such as compliant ZUGFeRD and Factur-X invoices are different. They combine a readable PDF with embedded structured XML data. Images in JPG, TIFF, and PNG formats fall into the same category, including those processed with OCR. A team that still downloads, opens, and keys invoice data into the accounting system relies on manual invoice processing, regardless of how the invoice arrives. Sorting incoming invoices into those that arrive as data and those that arrive as documents shows how much of an invoice processing workflow still depends on manual entry.

The table below compares the three most common invoice types.

Brex

E-invoicing mandates are pushing companies to act

Several European countries now require businesses to receive or issue structured e-invoices, with scope, exceptions, and transition periods that differ by country.

Some mandates add e-reporting, in which businesses also report invoice or transaction data to tax authorities on top of exchanging the invoice itself. France’s e-reporting dates are one example, and the Commission’s Belgium factsheet lists e-reporting as planned for 2028. Many of these mandates cover both receiving invoices from suppliers and issuing invoices to customers. A company that operates in or sells into these markets can face the requirement as an issuer as well as a receiver of invoices. Requirements and dates can change, so confirming current rules with a tax advisor before making decisions is a sensible step.

E-invoicing vs. AP automation vs. supplier portals

These three terms are often conflated, and separating them shapes how a team evaluates tools. E-invoicing covers how invoice data is formatted and transmitted, and it lives on the supplier's side and in the channel between platforms. AP automation covers what happens after the invoice arrives, and validation, GL coding, approval routing, payment execution, and ERP sync all fall within its scope, whether the incoming invoice is a structured e-invoice or a PDF from which an AI tool has extracted data.

Supplier portals are one channel through which suppliers may submit invoices. They provide a submission interface, while the invoice format remains separate. The table below compares the three terms.

Brex

Common e-invoicing formats and standards AP teams should know

Knowing common e-invoice formats helps a team ask the right questions during a platform evaluation and tell a real structured invoice exchange from a relabeled PDF workflow. Most AP teams do not need to read the underlying schemas, only enough context to spot the difference. The formats below appear in current European mandates and in the exchange networks AP teams may meet.

UBL 2.1 (Universal Business Language) is a standard XML format and the syntax behind the Peppol BIS Billing 3.0 invoice. If an ERP connects through Peppol, it is likely exchanging invoices in UBL.
CII (Cross-Industry Invoice) is an XML syntax from UN/CEFACT that appears alongside UBL in the German and French factsheets. A receiving platform can ingest it without manual re-keying.
ZUGFeRD and Factur-X are hybrid formats that pair a human-readable PDF with machine-readable XML. The PDF layer is readable by anyone, while the XML is machine-processable by the buyer's AP system, which can make hybrids a practical transition format for companies whose trading partners range from fully automated to still manual.
EDI standards such as EDIFACT and ANSI X12 are older data-exchange standards between trading partners. X12 is maintained by a body chartered by the American National Standards Institute, and its standards are used across supply chain, transportation, government, finance, and health care.
Country-specific requirements sit on top of these formats in some markets. Germany’s factsheet references XRechnung, and Poland uses KSeF as its national e-invoicing system, so companies with suppliers or customers in mandate-active countries may need to support the relevant format.

E-invoicing networks

Networks solve the coordination problem by letting suppliers and buyers connect once and then exchange invoices with other participants, which removes the per-partner integration work of point-to-point setups. The network a supplier uses affects onboarding effort and exception handling when a program is being set up. The examples below show how a European network, a U.S. network, and national platforms each approach the problem.

Peppol is an e-invoicing network and set of specifications. Its Peppol BIS Billing 3.0 invoice uses UBL syntax, and the European Commission factsheets for Belgium and Poland both reference it.
DBNAlliance is an open exchange network for B2B e-invoices and e-documents in the United States. It follows a four-corner model in which the supplier's access point finds the buyer's access point, packages the invoice into the exchange standard, and sends it securely so the buyer's access point can forward the data into the buyer's AP system.
National and government platforms operate in some countries. Poland's KSeF is one example, and France routes invoices through accredited private platforms, so companies with operations in these markets may need to confirm how outbound invoices must be delivered.

5 benefits of e-invoicing for AP teams

The five benefits below describe what can change for a finance team managing AP at a midsized company or growing startup. Each one ties back to the same operating question, which is how much manual work still sits between invoice receipt and posting. They run in workflow order, from intake through visibility into the AP pipeline.

Fewer manual touches per invoice

Structured intake can cut the number of times a person handles each invoice. When invoice data arrives already structured and validated, a team can shift from keying each invoice to reviewing exceptions, and that time can get redirected to higher-value work like cash flow forecasting or supplier relationship management. Reducing keying is the core idea behind automated invoice processing, and fewer touches can also mean fewer keying errors reaching the ledger.

Earlier error detection

Fewer manual touches also change where errors show up. Automated validation at invoice receipt can catch issues such as duplicate invoices, missing fields, and purchase order mismatches before any human reviews the record.

This matters for fraud exposure, too. Duplicate payments and altered vendor details are easier to catch when a system checks every invoice against the same rules, instead of relying on a person to notice that something looks off. Discrepancies surface as exceptions at intake, while there is still time to resolve them before close. AP accruals can become more accurate because the queue of invoices received but not yet approved is more real-time and more complete. For controllers preparing for an audit, the difference between catching errors on day one and on day 25 can determine whether a close runs cleanly or turns into cleanup work.

Duplicates can appear even in simple workflows. Catching duplicates at intake is the kind of control that separation of duties and consistent validation rules can support, since no single person has to remember what was already paid.

Faster approval cycles

Approvals move faster once invoice data arrives clean and exceptions are flagged early. Approval chains running over Slack and email can be hard to track, and no one knows where an invoice is sitting or who is holding it up. Invoices routed through an AP automation platform follow configured logic, so each one takes a defined path the moment it clears validation, and approval thresholds can mirror a written accounts payable policy. Cycle times often shorten, and late-payment penalties and missed early-payment discounts become easier to control. Configured approval logic gives finance a workflow it can monitor and audit in one place.

Stronger audit trail and compliance posture

Faster routing also improves the record a team keeps along the way. Each step of the e-invoice lifecycle, from receipt through validation, coding, approval, and payment, gets logged against the invoice record. For finance teams managing audits or preparing for mandate compliance, this can create a defensible timestamped record without hours of manual documentation effort. The shift toward paperless accounts payable supports audit readiness in markets where structured invoice data is legally required, and keeping source files attached to the record is part of accounts payable document management.

Real-time visibility into the AP pipeline

A complete audit trail also gives finance better visibility into what is moving through AP right now. Structured invoice data offers a live view of each invoice's status, including whether it is received, in validation, pending approval, or scheduled for payment. That view matters for cash flow management when invoices would otherwise sit in a shared inbox and a spreadsheet. Finance can see which payment runs can be shifted without penalty, how much AP is in flight, and where committed spend diverges from approved invoices. Regular accounts payable reporting on those statuses helps a team move from reactive processing to proactive cash management, and the same data supports tracking of invoices and payments in one place.

How e-invoicing works for AP teams, step by step

Once a supplier and buyer are both set up for e-invoicing, the invoice lifecycle can run platform-to-platform from creation to payment. Invoice data moves directly into the AP process, which can eliminate much of the manual handling required by PDF and email workflows. The six steps below show where structured intake changes the workload for finance teams.

Step 1. Supplier generates a structured invoice

In their billing platform or ERP, the supplier creates an invoice output in a structured data format. The output file might be XML, UBL, or a country-specific schema, and the fields typically include vendor ID, PO number, line-item descriptions, quantities, unit prices, tax codes, and payment terms. The result is a machine-readable file that a receiving platform can parse without re-keying by the AP team. The rest of the workflow depends on this step working correctly.

Step 2. The invoice travels system to system

Three common channels handle delivery from supplier to buyer. The right mix depends on supplier volume and on which networks the supplier base already uses. In each of the three, the AP team receives the invoice data directly in the platform, which can reduce intake friction before approvals begin.

A direct API or EDI connection between supplier and buyer platforms works for high-volume strategic relationships where bilateral setup is worth the investment.
An e-invoicing network such as Peppol or DBNAlliance lets both parties connect once and exchange invoices with other participants on that network.
A supplier portal hosted on the buyer's AP platform may provide suppliers with a web interface for submission.

Step 3. The AP system receives and validates

The invoice enters the AP queue as a pre-populated draft. Automated validation runs immediately, checking invoice data against purchase orders and receiving documents. Discrepancies surface as exceptions at intake, and invoice matching rules flag mismatches between the invoice, the purchase order, and the receiving documents. Two-way matching compares the invoice with the purchase order, and three-way matching adds the receiving document. Matching at intake keeps a team focused on the exceptions that need judgment.

Step 4. Automated GL coding and matching

Coding rules and historical transaction patterns can map vendors, GL accounts, departments, cost centers, and projects. Where POs exist, matching against purchase orders and goods receipts can run automatically, leaving only true exceptions for human review. Coding delays can stall invoices, and a clear purchase order management process gives coding rules more to work with.

Step 5. Approval routing

Invoices that pass validation are routed to approvers based on configured rules such as amount thresholds, vendor, and employee role. Below-threshold invoices that meet matching criteria can be auto-approved, with the decision logged against the invoice record. Comments, changes, and escalations get captured automatically, so a team does not have to chase approvers through email. Sequencing, reminders, and escalation can happen without manual intervention, creating a cleaner approval path and a clearer audit record.

Step 6. Payment execution and ERP sync

Approved invoices post to AP in the ERP, whether that is NetSuite, Sage Intacct, QuickBooks, Xero, or another platform. Payment runs can be triggered from the same platform by ACH, wire, check, or card, and how long ACH payments take to process affects how teams schedule them. The lifecycle from structured data receipt to payment confirmation can live in a single audit trail, with far less manual reconciliation across systems. At this stage, a team reviews exceptions and confirms payment runs while the platform handles data entry and signature chasing, which is where payment automation tends to pay off.

How to choose e-invoicing software for AP teams

E-invoicing software covers a range of tools, from network access points that exchange structured files to AP platforms that process whatever arrives. Evaluations tend to go more smoothly when buyers ask where in the workflow each tool starts and stops. The criteria below reflect the distinction drawn earlier between structured exchange and AP automation.

Intake method covers whether the product ingests structured files such as UBL and CII or captures data from PDFs and images with OCR and AI, since the two approaches leave different amounts of manual review.
Network and mandate coverage covers which networks and countries the product supports, such as Peppol or DBNAlliance, when suppliers or customers sit in mandate markets.
Validation and matching covers whether the product validates invoices at intake and matches them to POs so exceptions surface before approval.
Approvals and audit trail covers configurable routing, thresholds, and a timestamped record of each step.
ERP sync and payments covers which accounting systems the product syncs with and which payment methods it can trigger.

Shortlists often start with comparisons of the best AP automation software, and the evaluation then narrows to criteria from guidance on how to choose accounts payable software, such as integrations, controls, and support. Asking each vendor to demonstrate an invoice moving from intake to posting, using the formats the supplier base actually sends, tends to surface differences quickly. Buyers who see the same invoice handled end-to-end can compare intake methods, exception handling, and approvals on equal terms.

E-invoicing best practices for AP teams

E-invoicing rarely goes live overnight. These practices can make the difference between a clean rollout and a six-month supplier-onboarding slog. They also help a team avoid replacing one backlog with another.

Starting with the highest-volume suppliers

If 20% of suppliers generate 80% of invoice volume, those suppliers are where e-invoicing can pay off first. A team might identify top suppliers by invoice count, check whether they already use billing software or an ERP that can output structured data, and prioritize those for onboarding. When onboarding a high-volume supplier, additional transaction types such as order acknowledgments and payment remittances can be configured at the same time. Setup effort can spread across transaction types this way, and a phased rollout that expands gradually from the highest-volume suppliers is more achievable than a whole-catalog flip.

Cleaning up vendor master data before go-live

A phased rollout works only if the underlying data is clean. E-invoicing validation runs against the vendor master, so IDs, tax identifiers, GL mapping, and payment terms all matter. If that data is inconsistent or incomplete, structured invoices will fail validation at intake, creating a different kind of exception backlog. Before go-live, finance teams commonly deduplicate supplier records, standardize PO formats and tax codes, archive inactive vendors with a clear time threshold, and assign default GL accounts and cost centers, so automated coding rules have clean data to work with. One-time cleanup is not enough, and regular audits are among the core accounts payable best practices for preventing duplicate payments, fraud, and data drift that quietly undermine AP automation.

Handling the hybrid reality

Clean master data matters because many AP teams at midsized and growing companies are likely to run a mixed environment during a transition. Some suppliers send structured e-invoices, others send PDFs, and a handful of small vendors may still mail paper. The workflow benefits from processing all three through a single validation and approval path, since parallel queues can erode the gains from automation.

Defining success metrics before rollout

A hybrid intake model still needs a clear way to measure progress. Common KPIs include invoice touch count per invoice, average cycle time from receipt to payment, the percentage of invoices processed straight through, and error rate per 100 invoices. Establishing a baseline before go-live lets the impact show up in the numbers a team already tracks, and published industry benchmarks can add an external reference point. An internal baseline also makes the business case defensible to leadership and helps distinguish implementation noise from a real process improvement.

Aligning the e-invoicing intake layer with the AP automation layer

Once metrics are defined, the final implementation step is making the workflow hold together from intake through posting. E-invoicing handles upstream formatting and transmission, while AP automation handles downstream processing, and the two need to connect cleanly. Teams commonly confirm ERP integration design, GL coding-rule mapping, and exception-handling logic before onboarding the first supplier to a structured network. Finance, tax, IT, and operations all benefit from being in scope, since siloed initiatives make implementation harder and increase the likelihood of exception-handling and reconciliation problems later.

Build your e-invoicing strategy on the right AP foundation

For finance teams at midsized companies, e-invoicing is largely an efficiency decision. Each invoice that arrives as structured data can reduce manual keying, GL coding, and month-end chasing. For invoices that still arrive as documents, AI-powered capture can automate much of the same workflow while suppliers transition over time.

This story was produced by Brex and reviewed and distributed by Stacker.