AI invoice processing: how software reads, matches and posts supplier invoices
AI invoice processing software reads a supplier invoice from email or a scan, pulls out the supplier, lines, taxes and total, and matches it to the purchase order and the receiving record. When something differs, such as a higher price or a short shipment, it sends the invoice to a person to approve before anything is posted to the ERP or accounting system. For a Canadian company the same check covers the supplier’s GST/HST and QST registration numbers, which most invoices must show before you can claim that tax back. This guide walks through each step, the controls that keep it safe, and the software on the market.
What invoice processing is
Invoice processing is the accounts payable work between a supplier’s invoice arriving and the payment going out. Accounts payable (AP) is the money a company owes its suppliers, and the name of the team that pays it. The steps are the same at a small distributor and a large plant, and the table shows which part of each step software can take on.
| Step | What happens | What AI can take on |
|---|---|---|
| Receive | Invoices arrive by email, supplier portal or post | Watch a shared mailbox and pick up each attachment |
| Capture | Someone types the supplier, invoice number, date, lines, taxes and total | Read those fields from the PDF or scan |
| Code | Each line gets a general ledger (GL) account, the category it is booked to | Suggest the account from past invoices from the same supplier |
| Match | The invoice is checked against the purchase order and the receiving record | Compare prices and quantities within set tolerances |
| Approve | A person with authority signs off, especially on differences | Route the invoice to that person with the differences listed |
| Post and pay | The bill is entered in the ERP or accounting system and paid on its terms | Draft the entry so a person can post it |
Microsoft describes its own AP agent for Business Central this way: it “monitors mailboxes for incoming vendor invoices, uses AI to analyze invoice content, and shows invoice drafts to agent supervisors for review.” The typing and the first check move to software. The judgment calls stay with people: whether a price increase was agreed, whether a short shipment should be paid in full, and whether a new supplier is real.
How AI reads an invoice
Reading an invoice takes two kinds of AI. Optical character recognition (OCR) turns the image of a page into text. A second model decides which text is the invoice number, which is the total and which rows are line items. Microsoft’s Document Intelligence invoice model, for example, extracts “key fields and line items” from “phone-captured images, scanned documents, and digital PDFs,” and reports a confidence value, the model’s own estimate of how sure it is, with what it extracts. Oracle says NetSuite Bill Capture uses a “large multimodal model,” one that reads the page image and its text together, to handle “complex invoice formats, such as those with multiple columns, mixed content types, and unstructured or free-text layouts.”
Hard cases include line items that run over two pages, credit notes laid out like invoices, a packing slip scanned with the invoice, and suppliers who put the PO number in a different place each time. Test the software on your own invoices before you trust any accuracy figure. Text extraction from images explains how to run that test.
Three-way match: invoice, purchase order and receipt
A purchase order (PO) is the buyer’s written order to a supplier, with items, quantities and prices, and the purchase order template shows the usual fields. A receiving record, called a product receipt in some ERPs, records what arrived at the dock. The ERP is the business system that holds orders, inventory and accounting. Microsoft’s documentation for Dynamics 365 Finance defines four ways to match an invoice.
| Match type | What Microsoft’s documentation says is compared | Where it fits |
|---|---|---|
| Invoice totals | “the total amounts on the invoice to the total amounts on the purchase order” | Low-value purchases where line detail matters less |
| Two-way | “the price information on the invoice to the price information on the purchase order” | Services, or goods with no receiving step |
| Three-way | The same price check, plus the invoice quantity against “the quantity information on the product receipts” | Stocked goods, raw material and parts |
| Charges | Charges such as freight on the invoice against the charges on the purchase order | Suppliers who add freight, fuel or handling fees |
A tolerance is the difference you accept without a review. Microsoft’s example is a purchase order for 1,000 batteries at 1.00 each, a 5 percent price tolerance, and an invoice at 1.10. “A price of 1.05 would be acceptable, but 1.10 is not,” so the invoice waits until the difference is resolved. Tight tolerances send more invoices to review, and loose ones let small overcharges through, so set them by supplier or item group, which Microsoft’s software allows.
What gets flagged for a person
An invoice from a regular supplier against a clean PO should pass. The rest need a decision, and the software’s job is to put the evidence in front of the right person.
| Flag | What the software sees | Who usually decides |
|---|---|---|
| Price over tolerance | The invoice unit price is above the PO price by more than the set tolerance | The buyer who placed the order |
| Billed more than received | The invoice quantity is higher than the receiving record | Receiving, or the buyer |
| No purchase order | No PO number, or a number that does not exist in the ERP | The person who ordered, or their manager |
| Possible duplicate | Same supplier and invoice number, or the same amount and date as an earlier invoice | Accounts payable |
| New supplier or new bank details | A supplier not in the vendor list, or payment details that differ from the record | Finance, after a phone call to a number already on file |
| Tax does not fit | A missing registration number, or a tax that does not match the ship-to province | Accounts payable, or your accountant |
| Charges not on the PO | Freight, surcharges or fees the order did not include | The buyer |
Each flag should show its evidence beside it: the PO line, the receiving record, the earlier invoice or the result of the tax number check. Human in the loop covers how to design an approval screen that people read before they click.
GST/HST and QST checks on a Canadian supplier invoice
To claim back the GST/HST you paid, called an input tax credit (ITC), you need an invoice that carries certain information, and the list grows with the amount. The table is the CRA’s list from its input tax credit page, checked September 28, 2026.
| Information on the invoice | Under $100 | $100 to $499.99 | $500 or more |
|---|---|---|---|
| Supplier’s business or trading name | Yes | Yes | Yes |
| Invoice date | Yes | Yes | Yes |
| Total amount paid or payable | Yes | Yes | Yes |
| GST/HST charged, or a statement that the price includes it | No | Yes | Yes |
| Which items are taxable, when an invoice mixes taxable and exempt items | No | Yes | Yes |
| Supplier’s GST/HST registration number | No | Yes | Yes |
| Buyer’s name | No | No | Yes |
| Brief description of the goods or services | No | No | Yes |
| Terms of payment | No | No | Yes |
Quebec’s QST works the same way through input tax refunds (ITRs). Revenu Québec’s list, checked the same day, uses the same thresholds, counted on the total including taxes, with two differences: the QST amount and a description of the goods are required at every amount, and from $100 the invoice must show the supplier’s QST registration number as well as its GST number.
Software can check the numbers. The CRA’s GST/HST Registry lets you “confirm that the business charging you GST/HST is registered,” which the CRA says helps ensure “that your claims for input tax credits only include GST/HST charged by someone who is registered for GST/HST.” Revenu Québec offers an API, a connection other software can call, that validates a QST registration number and returns its status, its effective date and the business’s name. A QST number has “ten digits followed by the letters TQ and four more digits.”
The tax charged should also fit the province. The CRA’s rate table, checked September 28, 2026, lists 13% HST in Ontario, 5% GST plus 9.975% QST in Quebec, and 14% HST in Nova Scotia since April 1, 2025. It adds that the rate depends on the type of supply, where it is made and who it is made to. Software can flag an invoice whose tax does not fit the ship-to address, and your accountant settles the edge cases.
Posting to the ERP or accounting system
The last step writes the bill into your system of record. Where the ERP or accounting system has an API, a connection one program uses to call another, the software can create the bill directly. The safe pattern is a draft: the software fills in the bill, a person reviews it, and only that approval posts it. Microsoft says its Payables Agent “creates drafts only and never automatically posts invoices,” and QuickBooks Online has you review each uploaded bill before you create it.
Many plants run an older ERP with no API. A computer use agent, software that works the ERP’s own screens the way a clerk does, can key each approved invoice. Legacy ERP automation explains how that works, and AI for ERP covers the wider options.
Keep the invoice image attached to the entry. The CRA’s records page, read September 28, 2026, says you must generally keep records and supporting documents “for a period of six years from the end of the last tax year they relate to,” at your place of business or residence in Canada unless it gives written permission to keep them elsewhere. If an AP service stores your invoices outside Canada, ask your accountant how that rule applies.
See your own invoices read and matched
Tell Derik which ERP you run and roughly how many supplier invoices arrive each month. He will tell you which steps can be drafted by software and which should stay with your team.
Start a conversationAccuracy and controls
Measure accuracy on your own invoices before you trust any figure. Take about 100 recent invoices from your main suppliers, let the software read them, and compare each field with what your team entered: supplier, invoice number, date, every line, tax and total. Count an invoice as correct only when every field is correct, since one wrong field can change what you pay. Then run it alongside your team for a month, with the software drafting and people still entering, and let it do more only where the comparison supports it.
The controls that matter most sit around the AI:
- Bank detail changes. The Canadian Anti-Fraud Centre describes fraudsters who send “a spoofed email informing the business of a change in payment details” with new banking information. Confirm any change by calling a number you already have on file. Microsoft notes that vendors and their bank accounts are usually approved through “human callbacks to the vendor’s finance department.”
- Approval limits. Set an amount above which a second person approves, and let the software route by amount.
- Separate duties. The person who adds a supplier or edits its bank details should not approve that supplier’s invoices.
- Duplicates. Check the supplier and invoice number, and near matches on amount and date.
- A record of every decision. Keep the AI’s suggestion, the person who approved it, any change they made and when. Microsoft says every action of its agent is attributed to the agent’s own user, “providing complete audit trails and traceability.”
- Text aimed at the AI. An invoice PDF can carry hidden instructions meant to mislead a model. Microsoft says it tested its agent “with malicious invoice content.” AI security explains this risk, called prompt injection.
AI invoice processing software, and what each vendor says
ERP and accounting vendors now build invoice reading into their own products, and specialist AP tools sit alongside the ERP. The descriptions are the vendors’ own, checked September 28, 2026.
| Product | What the vendor says it does | Worth knowing |
|---|---|---|
| Microsoft Dynamics 365 Business Central Payables Agent | “monitors mailboxes for incoming vendor invoices, uses AI to analyze invoice content, and shows invoice drafts to agent supervisors for review” | PDF invoices only. Microsoft lists approval flows and anomaly detection among the features it currently does not support. It is billed per use in Copilot Credits, counted per invoice and per invoice line |
| Oracle NetSuite Bill Capture | “you can email or upload vendor bill files to create NetSuite vendor bills” | Its suggestions “rely on matches with NetSuite records, such as vendors, items, and purchase orders” |
| Sage Intacct AP Automation | “Upload or email an AP bill and Sage Ai will automatically extract details and create a pre-populated draft for your approval” | Sage says it “automates matching to purchase orders” and “flags duplicate invoices” |
| QuickBooks Online | “We extract info from it and create a transaction for you to review” | Accepts PDF, JPEG, JPG, GIF and PNG files |
| Stampli | “Billy codes, matches, and routes invoices with every question and decision attached” | Billy is the name of Stampli’s AI assistant |
Ask each vendor how it charges, for example per user, per invoice or by quote, and check its own pricing page. Ask too where invoices are stored and where the model runs. Microsoft’s FAQ notes that if a Business Central environment is in a country or region where Azure OpenAI is not available, “administrators must allow data to move across geographies.” Private AI for business lists the questions to put in writing. Invoices and purchase orders are also where procurement starts, and AI in procurement covers the buying side.
How ThriveAI helps
ThriveAI is an AI engineering company in Ottawa that builds private AI systems on a client’s own data, for manufacturers and distributors in Ontario and Quebec. For accounts payable, it builds the process on this page around your own records: invoices read from your AP mailbox, matched to your purchase orders and receiving records, and drafted in your ERP for a named person to approve. The platform is designed to keep each client’s data on its own server in Canada. The client chooses a model on that server or a hosted model under a written zero data retention agreement, a contract under which the provider keeps no copy of a request or its answer. A hosted model may process requests outside Canada. Derik Lawlis, the founder, leads every project and stays close to the build. More is on About ThriveAI.