# What Is E-invoicing For Accounts Payable And How Does It Work?

Most AP teams receiving PDFs by email aren't doing e-invoicing. Learn what structured invoice exchange means, which formats matter, and how to implement it.

**URL Source:** https://www.brex.com/spend-trends/cash-flow-management/e-invoicing

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What is e-invoicing? A guide for accounts payable teams

### 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 US 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.



### Introduction



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. The distinction matters because many AP software vendors use "e-invoicing" loosely, and buyers can end up with platforms that still require manual work at intake.

This guide 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 US 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. We suggest you use this guide along with your professional advisor when making business decisions.



### 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 however 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](https://www.brex.com/spend-trends/cash-flow-management/invoice-processing) workflow still depends on manual entry, and the table below compares the three most common invoice types.





### 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, and teams that want more detail on the downstream side can review [AP automation](https://www.brex.com/spend-trends/accounting/ap-automation).





### 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 US 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](https://www.brex.com/spend-trends/cash-flow-management/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, because 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. [ONEflight International](https://www.brex.com/resources/customer/oneflight-international) CFO Hanno Uys described it in a Brex customer story, saying "A lot of times the flight coordinators will send us a quote and then they will send a quote and an invoice, so Brex identifies when there are duplicates, so we can easily make sure we don't pay something twice." Catching duplicates at intake is the kind of control that [separation of duties](https://www.brex.com/spend-trends/accounting/separation-of-duties-in-accounting) 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](https://www.brex.com/spend-trends/accounting/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](https://www.brex.com/spend-trends/accounting/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](https://www.brex.com/spend-trends/accounting/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](https://www.brex.com/spend-trends/accounting/accounts-payable-reporting) on those statuses helps a team move from reactive processing to proactive cash management, and the same data supports keeping track of [invoices and payments](https://www.brex.com/spend-trends/accounting/how-to-keep-track-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](https://www.brex.com/spend-trends/accounting/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](https://www.brex.com/spend-trends/procurement/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](https://www.brex.com/spend-trends/business-banking/how-long-do-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](https://www.brex.com/spend-trends/cash-flow-management/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](https://www.brex.com/spend-trends/accounting/best-ap-automation-software), and the evaluation then narrows to criteria from guidance on [how to choose accounts payable software](https://www.brex.com/spend-trends/accounting/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](https://www.brex.com/spend-trends/accounting/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.

Brex customers can submit invoices to bill pay as PDFs, images, and several other file types, with email submissions handled in English and USD at one invoice per email. AI pre-fills the invoice fields, and a user can adjust any field that is read incorrectly. Capture from documents is a different job from ingesting structured e-invoice files such as UBL, so teams with suppliers in mandate markets benefit from confirming how any AP platform handles those formats. For invoices that still arrive as scans or images, OCR can capture the data until the supplier converts, which lets a team run one workflow however the invoice arrives.

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.

Brex is the intelligent finance platform for startups and growing businesses, and its [bill pay](https://www.brex.com/product/bill-pay) lets customers upload invoices or forward them to a unique email address, with AI pre-filling the fields for review. Bill pay two-way matches bills to a purchase order and flags bills that are missing one, and the Policy Engine routes bills for approval based on amount and vendor. Approved bills sync to QuickBooks Online, NetSuite, Sage Intacct, and Xero through Brex [integrations](https://www.brex.com/product/integrations), and customers can pay by ACH, wire, check, or one-time virtual card. Teams can also use Brex [corporate cards](https://www.brex.com/product/credit-card) and a [business account](https://www.brex.com/product/business-account) alongside bill pay, and some bill pay capabilities depend on plan.

At [ONEflight International](https://www.brex.com/resources/customer/oneflight-international), flight coordinators email invoices to Brex, and the platform captures the details with OCR. The controller reviews the populated bills in minutes, and the CFO bulk-approves them from a pending approval list. Hanno Uys, the CFO, described that step by saying "I have the list under pending approval, and I can go through and tick all the ones that are relevant, and approve." He reported that he and his controller each save about four hours a day on wire processing.

[Book a demo](https://www.brex.com/book-a-demo) or sign up to see how Brex can support your invoicing and AP workflows.

_Created with AI assistance and reviewed by Brex. This article reflects Brex's perspective at the time of publication and is intended for general informational purposes only. It is not intended as legal, tax, accounting, or financial advice. Laws, regulations, and guidance may vary based on your specific circumstances, and interpretations or outcomes may differ. Information may also change over time. Before making any decisions, you should consult your own qualified legal, tax, accounting, or financial advisors._

_The testimonials on this website are from actual Brex and Brex Treasury clients, and reflect their personal experiences and opinions. Please note:_

- _Testimonials may not represent the experiences of all clients, which can vary based on individual goals, market conditions, and services used._
- _They are not guarantees of future results. All investments carry risk, including potential loss._
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## Frequently asked questions about e-invoicing

### What is an e-invoice and how does it work?

An e-invoice is an invoice issued as structured, machine-readable data that a buyer's accounting or AP system can read and process without manual re-keying. The supplier's system creates the file and sends it over a network, API, or direct connection, and the buyer's system validates it and moves it into approval and payment.

### Is e-invoicing the same as emailing a PDF invoice?

No, e-invoicing delivers structured data that a system can read directly, while a PDF sent by email delivers a document whose data needs extraction by OCR, AI, or manual entry before processing.

### Does e-invoicing work with NetSuite, QuickBooks, and other accounting systems?

Yes, e-invoice data can reach NetSuite, QuickBooks, Xero, Sage Intacct, and other accounting systems through an AP platform or access point that supports the integration. Invoice data maps to GL accounts, departments, and cost centers through configured coding rules, and Brex bill pay syncs bills to QuickBooks Online, NetSuite, Sage Intacct, and Xero.

### Is e-invoicing required in the US?

Requirements in the US vary by situation, and federal agencies receive vendor invoices through the Treasury's [Invoice Processing Platform (IPP)](https://www.ipp.gov/about), which is offered at no charge to federal agencies and their vendors. Mandates in other countries, customer contracts, and agency rules can all call for structured invoices, so confirm current requirements with a tax advisor.

### Who is required to do e-invoicing?

Businesses in countries with e-invoicing mandates, such as Belgium, Germany, France, and Poland, must receive and in many cases issue structured invoices once the relevant phase-in date arrives, based on revenue thresholds and jurisdiction. Dates and thresholds change, so confirm current requirements with a tax advisor.

### Is e-invoicing difficult to set up?

Setup effort grows with supplier count, ERP complexity, and the number of formats involved. Brex bill pay handles emailed and uploaded invoices in one workflow, which can reduce the number of separate intake processes a team maintains while suppliers transition.

### What happens to suppliers who can't send structured invoices?

Those suppliers can keep sending PDFs or images, and an AP platform with AI-powered capture can extract the data so the invoice follows the same validation and approval workflow. Human review can then focus on exceptions while suppliers move to structured formats over time.

### Can a shared AP inbox work as an e-invoicing process?

A shared inbox collects invoice documents, so someone or something still has to extract and enter the details before processing. Brex customers can forward invoices to a unique email address, where AI pre-fills the bill fields for review.

### How can teams prevent duplicate invoice payments?

Matching each invoice to a PO and checking invoice number, vendor, and amount against prior records at intake helps catch duplicates before payment. Brex bill pay includes a duplicate bills filter for reviewing bills flagged as duplicates.