To automate purchase invoices, a workflow collects every incoming invoice and reads the required fields. It checks them and places a draft entry in your accounting software. You only review the exceptions. I explain which fields and checks belong in it. Then I work out what it saves and which rules apply in 2026.
The timing matters. Belgium has required structured e-invoices between VAT-registered businesses since 1 January 2026. From 1 July 2030 the EU directive known as VAT in the Digital Age makes e-invoicing the default for cross-border B2B trade. If you build your purchase invoice flow now, make it handle both PDF and e-invoice.
How do you automate purchase invoices in practice?
In automated invoice processing, every purchase invoice follows six fixed steps. It arrives at one address. The workflow reads the data and checks the amounts, the VAT plus the bank account. If everything matches, a draft entry waits in your accounting software. If something is off, a colleague decides. The original file always goes to the archive.
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- Receive. Suppliers send to one invoice address. Invoices in personal inboxes get lost or arrive twice.
- Extract. From a PDF, the workflow pulls the text and turns it into fixed fields. An e-invoice in UBL already contains those fields as data, so this step disappears.
- Check. Calculation rules and a comparison with your own supplier records. In my view this is where the real value sits.
- Draft entry. Supplier and ledger account are filled in. The VAT code and amounts are there too.
- Approve. You or a colleague approves. Above an amount you choose, a second person looks as well. I always recommend that.
- Archive. The original file stays linked to the entry, so you can find it later.
Fixed steps first, smart parts later. That structure also works for other processes, see business process automation. The extraction step may use a language model. Everything else is a fixed workflow with fixed rules. If you are new to the tool, start with what n8n is.
Which fields should you extract from a purchase invoice?
Take the Dutch Tax Administration list as the base. For each invoice received you record the date and invoice number. You also record the supplier name plus address. Add a description, the price excluding VAT per rate plus the VAT amount per rate. For trade with other EU countries you also record the supplier VAT number.
That list comes from the Belastingdienst page on recording invoices you receive (in Dutch, consulted 27 October 2026). I recommend building your extraction schema on exactly these fields. In n8n you can do this with the Information Extractor node, where you describe each field or supply a JSON schema. Add two fields the tax authority does not ask for: the IBAN on the invoice and the due date. You need them for the checks and for payment.
The invoice itself must meet the invoice requirements, or you risk your VAT deduction. The Belastingdienst lists the supplier VAT identification number and Chamber of Commerce number among them. A unique sequential invoice number, the supply date plus the applied rate belong on it as well. If one is missing, you want to know before you post.
Which checks make automated processing reliable?
Five checks together catch most errors. Does the total add up? Does the VAT amount match rate and base? Has this invoice number been posted before for this supplier? Does the IBAN match your own supplier records? Is the supplier known? If one check fails, the invoice goes to a person.
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| Check | What the workflow compares | On a mismatch |
|---|---|---|
| Total | Lines plus VAT against the invoice total | To review, with the difference shown |
| VAT | VAT amount against rate times base | To review, with the expected amount |
| Duplicate | Supplier plus invoice number against earlier entries | Hold and report |
| Bank account | IBAN on the invoice against your supplier card | Hold until someone calls |
| Supplier | Name plus VAT and company number against your master data | To review, propose a new supplier card |
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I consider the bank account check the most important one. The Dutch police explain how digital invoice fraud works. Criminals intercept a genuine invoice and change the account number. Then they forward it to the victim. Their tips to prevent it: always compare the account number with your own records. Verify the payment by calling the supplier on the number you already know. Never use the number on the payment request. The Dutch Fraudehelpdesk gives the same advice. The police also recommend that two people approve every payment order. A workflow can do the comparison on every invoice. Making the call stays a human job.
This keeps the workflow fast where it can be and careful where it must be. Want to see how the review step fits into your wider finance work? Read about our invoice process automation.
What does it save? A worked example
In this worked example a company processes 50 purchase invoices a week. By hand that takes about 153 hours a year. With automated processing 84 hours remain in a cautious case and 39 hours in the expected case. At the Dutch average hourly labour cost from Eurostat, that is worth €3,305 to €5,463 a year.
Run the numbers
EXAMPLE 1
The situation. A wholesaler with fifteen staff receives 50 purchase invoices a week, mostly as PDF by email. An employee opens each invoice and types the data over. Then they choose a ledger account and attach the PDF. In this example that takes 4 minutes per invoice.
The approach. A workflow reads each invoice and runs the five checks. Then it prepares a draft entry. An invoice that passes only needs a short review. A flagged invoice takes as long as it does today.
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| Assumption | Cautious | Expected |
|---|---|---|
| Invoices per week | 50 | 50 |
| Minutes per invoice, by hand | 4 | 4 |
| Working weeks per year | 46 | 46 |
| Share that passes without correction | 60 per cent | 85 per cent |
| Review time per passed invoice | 1 minute | 0.5 minute |
| Hours per year, by hand | 153 | 153 |
| Hours per year, automated | 84 | 39 |
| Hours saved per year | 69 | 114 |
| Value at €47.90 per hour | €3,305 | €5,463 |
The calculation. By hand: 50 × 4 × 46 / 60 = 153 hours. Automated: 50 × (share passed × review time + share flagged × 4) × 46 / 60. The value is hours saved times €47.90.
The result.
69 to 114 hours
less manual work a year in this worked example, worth €3,305 to €5,463 in labour cost
What goes worse than planned. The first weeks are harder. The share that passes without correction is lower at the start. New suppliers and unusual layouts need attention. Maintaining the workflow also takes time, and that is not in this sum.
Worked example with assumptions, not a client case. Hourly rate: Eurostat, 31 March 2026. Hourly labour cost in the Netherlands in 2025 was €47.90 (businesses with 10 or more employees, excluding agriculture and public administration). In Dutch trade it was about €40 according to CBS, so use your own labour cost.
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My advice is to use your own figures. Count your invoices for one week and time a single invoice honestly. A smaller volume saves proportionally less. At 10 invoices a week the expected case saves about 23 hours a year.
Accounting software, invoice processing software or your own workflow: which route fits?
I see three routes. The recognition built into your accounting software suits a simple flow and one system. Separate invoice processing software fits when approval by several people is the main job. Your own workflow fits when invoices pass through several systems or when you want your own checks.
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| Route | Fits | Strength | Watch out |
|---|---|---|---|
| Recognition in your accounting software | One package, few suppliers, modest volume | Available straight away, no extra system | Checks limited to what the package offers |
| Separate invoice tool | Several approvers, matching to purchase orders | Approval steps ready-made | Extra subscription and one more party with your data |
| Your own workflow, for example n8n on your own server | Several systems, own checks, data under your control | You decide the checks and where data lives | Needs maintenance and someone who reviews |
Software vendors say themselves that recognition is an aid. The Dutch package SnelStart states in its knowledge base that it offers no 100 per cent guarantee. You always need to check the imported invoices yourself. That applies to every route. For me the difference lies in which checks have already run.
If you use Exact Online, a workflow can create purchase entries through the API. Exact documents the PurchaseEntries endpoint for this. Exact limits the number of API calls per minute and per day, as its Knowledge Base explains. Look up the current limit for your subscription before you build. Read more on connecting Exact Online with n8n and on our wider system integrations.
When you should wait
- You receive fewer than about ten invoices a week. Your own workflow then gains little. The recognition in your accounting software is usually enough.
- Your supplier records are wrong. Without a correct IBAN and VAT number per supplier, the checks have nothing to compare against. Clean up your master data first.
- Nobody reviews the exceptions. A queue nobody empties is worse than manual work. Agree who checks it every day.
- Your suppliers already send e-invoices and your software reads UBL. Extraction then disappears and the gain lies mainly in approval. Start there.
Can you throw away the paper invoice after scanning?
In the Netherlands, yes, if the scan is a correct and complete copy of the original including its marks of authenticity. The Belastingdienst says so on its page about keeping invoices. You keep invoices for 7 years, or 10 years for immovable property. The digital version must remain auditable all that time.
If you process purchase invoices digitally, one rule matters: an invoice that arrives digitally must also be kept digitally. So keep the file as you received it: the PDF or the UBL file. A workflow can attach that original to the entry and store it in a fixed folder with a fixed name. Other countries have their own retention rules, so check yours.
Privacy matters too. An invoice from a sole trader contains the name of a person. The Dutch Chamber of Commerce (KVK) explains that the GDPR protects data about people, such as a sole trader. Data about a limited company is not covered. If invoices pass through a language model, decide where that data goes and sign a data processing agreement. More in the AI Act and GDPR in automation.
What changes with mandatory e-invoicing from 2030?
Council Directive (EU) 2025/516 makes e-invoicing the default for cross-border B2B trade within the EU. It applies from 1 July 2030, together with digital reporting. Member states may also require it for domestic trade. Belgium already does so since 1 January 2026, according to the Belgian government.
The Netherlands is following. On 11 September 2026 the Dutch government announced it wants to make e-invoicing between businesses mandatory from 1 July 2030. Domestic reporting follows from 1 July 2031. Businesses using the small business scheme, with up to €20,000 turnover a year, will be exempt. The draft bill goes to public consultation in autumn 2026 and to parliament before summer 2027.
What does that mean for your workflow? The share of PDF invoices will fall and the share of UBL will rise. Checks and approval stay necessary, and so does the archive. So build the route in a way that lets an e-invoice skip extraction and otherwise follow the same path.
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What does a purchase invoice workflow cost?
That depends on the number of sources and the checks. It also matters which systems the entry must reach. One mailbox into one package is a smaller project than three sources with order matching. After that you pay for maintenance and any model usage. See our pricing and package limits for the ranges.
Work out the payback period yourself. Subtract the monthly maintenance cost from the monthly value. Divide the one-time build cost by what is left. That gives you the number of months. Take the monthly value from the worked example above, divided by twelve. A fuller explanation is in our article on what business process automation costs.
Where do you start when you automate purchase invoices?
I always start with measuring and cleaning up. Only then do I build. Count a week of invoices and the time per invoice. Set up one invoice address. Complete your supplier cards. Let the workflow only propose entries at first and review the exceptions. Then extend the checks.
- Measure one week. Count invoices and the time per invoice. Note how many arrive as PDF, scan or e-invoice.
- One address. Ask suppliers to send to one invoice address.
- Master data in order. Per supplier the IBAN and VAT number, the company number plus a default ledger account.
- Proposals only. In the first weeks nothing is posted without approval. You see where the workflow hesitates.
- Extend the checks. Only when the share without correction is stable do you let more through.
Not sure this is the right process to start with? Read our guide to choosing your first process first. Before going live, it helps to know what running n8n in production involves. Accountants find a dedicated page on automation for accounting firms.
Key points
- A good workflow never posts on its own. It prepares a draft and sends exceptions to a person.
- Build your extraction schema on the fields the tax authority requires for invoices you receive.
- Comparing the IBAN with your own supplier records is the most important check against invoice fraud.
- In the worked example with 50 invoices a week, it saves 69 to 114 hours a year.
- From 1 July 2030 e-invoicing becomes the EU default for cross-border B2B trade. Build a route for UBL now.
Frequently asked questions
Can AI process invoices?
Yes, for reading them. A language model can turn a PDF into fixed fields such as supplier, date, amounts and VAT. In n8n the Information Extractor node does this with a schema you define. The model can misread a field. So let fixed rules check the total, the VAT and the IBAN, and send exceptions to a person. If invoices contain personal data, decide where the model runs.
What is 3-way matching in accounts payable?
Three-way matching compares three documents before you pay: the purchase order, the goods receipt or delivery note, and the invoice. Quantities and prices must agree. It suits businesses that buy through purchase orders. Many small businesses do not. For them the five checks in this article do the work: total, VAT, duplicate, IBAN and supplier.
What are the KPIs for invoice processing?
I would start with four that a small business can measure. Time per invoice from receipt to approval. The share of invoices that pass without correction. The number of exceptions per week and how long they wait. Duplicate or late payments. In the worked example above, the share without correction and the review time make the gap between 84 and 39 hours a year. Measure them for a week before you build.
What is a UBL invoice?
A UBL invoice is an e-invoice in Universal Business Language, a library of standard XML documents for business use such as orders and invoices. A profile fixes which fields you use and what goes in them. Software that supports UBL reads the invoice without recognition. In the Netherlands, SI-UBL 2.0 is the UBL implementation of the Dutch NLCIUS specification, according to the European Commission in its 2026 eInvoicing Country Sheet for the Netherlands.
What is touchless invoice processing?
Touchless processing means an invoice goes from receipt to posting without anyone touching it. It works best for e-invoices from known suppliers that pass every check. For PDFs it is riskier, because extraction can misread a field. A safer setup lets matching invoices through below an amount you choose. Above it, a person approves.
Sources
- Belastingdienst (Dutch Tax Administration), “Ontvangen facturen administreren” (in Dutch, consulted 2026-10-27)
- Belastingdienst, “Factuureisen” (in Dutch, consulted 2026-10-27)
- Belastingdienst, “Uw facturen bewaren” (in Dutch, consulted 2026-10-27)
- Rijksoverheid (Government of the Netherlands), “Kabinet kiest voor invoering e-facturatie en rapportage voor bedrijven”, in Dutch, 11 September 2026
- Council Directive (EU) 2025/516, VAT in the Digital Age, Official Journal of the EU, 25 March 2025
- Belgian government (FPS BOSA and FPS Finance), “Structured electronic invoices between companies are compulsory since 2026”, einvoice.belgium.be (consulted 2026-10-27)
- Eurostat, “EU hourly labour costs ranged from €12 to €57 in 2025”, 31 March 2026
- CBS (Statistics Netherlands), “De arbeidsmarkt in cijfers 2025”, in Dutch, chapter Lonen en loonkosten, 2026
- Politie (Dutch police), “Tips om digitale factuurfraude te voorkomen” (in Dutch, consulted 2026-10-27)
- Politie, “Wat is digitale factuurfraude?” (in Dutch, consulted 2026-10-27)
- Fraudehelpdesk, “Het rekeningnummer op de factuur is aangepast” (in Dutch, consulted 2026-10-27)
- European Commission, “2026 The Netherlands (2026 eInvoicing Country Sheet)” (consulted 2026-10-27)
- Forum Standaardisatie, “UBL” (in Dutch, consulted 2026-10-27)
- KVK, “Veelgestelde vragen over privacy en KVK”, in Dutch, updated 15 April 2026
- n8n Docs, Information Extractor; Extract From File; Email Trigger (IMAP) (consulted 2026-10-27)
- Exact Online, REST API reference PurchaseEntries; Knowledge Base API limits (consulted 2026-10-27)
- SnelStart Kennisplein, “Een inkoopfactuur of bonnetje automatisch inlezen in SnelStart Web” (in Dutch, consulted 2026-10-27)