Invoice automation with AI: from inbox to ledger

What invoice automation covers

Invoice automation is the part of accounts payable that takes a supplier invoice from the moment it lands in your inbox to the moment it waits in your accounting software as a coded, approved draft bill. Document automation is the wider name for the same technique applied to credit notes, supplier statements, delivery notes and expense receipts.

This guide is for a business processing its own purchase invoices. Template-based OCR reads fields from fixed positions on the page, so every new supplier layout needs a new template. A language model reads the document much as a clerk would, so it copes with a new layout, a scan or a phone photo without a template for each supplier.

How an invoice travels from inbox to ledger

1. 1
   Capture. Invoices reach a shared mailbox such as accounts@ as PDFs, scans or photos. Each attachment is picked up, files holding several invoices are split, and statements and remittance advice go to their own queue.
2. 2
   Read. The supplier, invoice number, dates, net, VAT, total and every line are extracted, and the lines are checked against the total.
3. 3
   Duplicate check. The supplier and invoice number are compared with bills already in the system, so an invoice sent twice is stopped before it is entered again.
4. 4
   Match. Each line is compared with the purchase order and, where you record deliveries, with the goods received note. Price and quantity must sit within the tolerance you set.
5. 5
   Code. A nominal code, cost centre, tracking category and VAT rate are suggested from the supplier’s history and your rules, each with a one-line reason.
6. 6
   Route. The draft goes to the approver your rules name for that amount, department or budget, with a reminder when it waits too long.
7. 7
   Post as a draft. After approval the bill appears in Xero, QuickBooks or Sage with the original PDF attached, ready for the payment run.

Exceptions and fraud checks

Invoices that fit the rules go straight to approval. The ones that do not are where finance loses time, so each exception reaches a named person with the reason stated and the invoice, order and supplier history side by side.

• No purchase order: the invoice goes to the budget holder to confirm or reject.
• Price or quantity outside tolerance: the difference is shown line by line next to the order.
• New supplier: nothing is entered until finance has set the supplier up through its usual checks.
• Changed bank details: if the invoice or covering email gives a sort code, account number or IBAN that differs from the one on file, the invoice is held. Someone in finance calls the supplier on a number already on record, never one taken from the email, before any detail changes.
• Warning signs: an amount far outside the supplier’s usual range, pressure to pay today or a sender address one letter away from the real domain is flagged as possible fraud.
• Low confidence: a blurred scan or a handwritten amount goes to a person with the unreadable fields highlighted.

What stays with finance

A person signs off every bill before it becomes final and every payment before it leaves the bank. Once a pilot has run cleanly, you may let one narrow category skip approval, such as a monthly utility bill within a set range of last month’s, and the log records every bill that used the rule. These stay with your team:

• Approving payments and releasing each payment run.
• Adding new suppliers and any change to a supplier’s bank details.
• The coding rules, approval limits and tolerances. The system applies them, and finance decides what they are.
• Supplier disputes, credit note requests and anything that needs a phone call.
• Month-end judgement: accruals, prepayments and the review before the books close.

What invoice automation costs

A pilot on one supplier inbox and one company costs £2,900 (£2,030 with the launch offer). It takes 2–4 weeks, and the test runs on a month of your past invoices. Matching against a purchasing system, several entities or approval chains across departments are built as a custom solution from £6,500 (£4,550). Care after launch is £350 a month (£245) and covers new suppliers, rule changes and monitoring. The AI providers charge usage per document to your own account at cost, and we estimate it from your monthly volume before launch. Prices exclude VAT.

An illustrative example: a business receives 400 supplier invoices a month, and keying each one in takes five minutes. That is about 33 hours a month, or roughly £730 at £22 an hour. If checking a prepared draft takes one minute, the monthly time drops to under seven hours. Put your own volumes and rates into the same sum.

How to run a first pilot

1. 1
   Export one month of supplier invoices together with the bills your team posted from them. That pair becomes the answer key for testing.
2. 2
   Write down approval limits, coding rules and order tolerances as they work today, including the ones that have never been written down.
3. 3
   Choose one inbox and one company. A second entity and staff expenses can follow once the first is stable.
4. 4
   Agree the metric before the build, for example minutes per invoice or the share of drafts approved without edits.
5. 5
   Run the system over last month’s invoices and compare every field with what was posted. Where they differ, adjust the rules.
6. 6
   Spend a week in shadow mode: drafts are prepared while the team keys invoices as usual, and the two are compared.
7. 7
   Switch to approving drafts, then go through the exception log together at the end of the first month.