Finance & FP&A

How to automate ap invoice approvals with AI

Finance & FP&A3 AI tools7 steps6 friction points

Want an agent to handle this on your live data? See the Starch version →

AP invoice approval is the process of routing vendor bills through the right reviewers, confirming amounts match purchase orders, flagging exceptions, and recording approvals before payment runs. For most small and mid-sized teams, this happens across a patchwork of inboxes, spreadsheets, and accounting software — meaning someone is manually chasing approvers, re-entering invoice data, and following up on overdue bills every week.

The workflow feels like an AI problem because the underlying tasks are rule-based and repetitive: extract line items from a PDF, match them to a PO, check amounts against a threshold, route to the right approver, send a reminder if no response in 48 hours. That structure is exactly what LLMs look good at in demos — parsing documents, applying logic, drafting messages — which is why operators keep reaching for ChatGPT or Claude to see if it can take this off their plate.

General-purpose AI tools can meaningfully help with parts of this workflow today. Claude is strong at extracting structured data from invoice PDFs and drafting exception summaries. ChatGPT handles approval routing logic well when you give it your rules in plain text. Gemini can cross-reference line items against a pasted PO. None of them can connect to your live accounting system, trigger emails, or persist the workflow so it runs automatically next week — but for one-off invoice review and drafting, they're genuinely useful.

Skip the manual work → See the Starch version

Finance & FP&A3 AI tools7 steps6 friction points

AI walkthrough

How to do it with AI today

A practical walkthrough using ChatGPT, Claude, and other off-the-shelf LLMs — what they're good at, what you'll have to do by hand.

Tools that work for this

ClaudeChatGPTGemini

Step-by-step

1 Export or screenshot the incoming vendor invoice as a PDF or image. If the invoice is in your email, download the attachment manually — there's no live inbox connection.

2 Paste the invoice content into Claude and ask it to extract vendor name, invoice number, date, line items, totals, and any payment terms into a structured table. Claude handles messy PDF formatting better than most models for this step.

3 Copy your purchase order data (from QuickBooks, NetSuite, or a spreadsheet) and paste it alongside the extracted invoice data. Ask Claude to flag any line items where the invoiced amount exceeds the PO amount by more than your defined threshold (e.g., 5%).

4 Paste your approval routing rules into ChatGPT — for example, 'invoices under $5,000 go to the team lead; $5,000–$25,000 go to the CFO; above $25,000 require board sign-off' — and ask it to determine the correct approver and draft a short approval request email for that invoice.

5 Copy the drafted approval email into your email client and send it manually. Set a calendar reminder to follow up if you haven't heard back in 48 hours — there's no automated nudge.

6 When approval comes back, manually update your AP tracker (a spreadsheet or your accounting software) to mark the invoice as approved and queue it for the next payment run.

7 Repeat this entire sequence for each invoice in the batch. For a team receiving 30+ invoices a week, this process runs in parallel across multiple tabs and becomes its own part-time job.

Prompts you can copy

Extract all line items, totals, vendor name, invoice number, and payment terms from the following invoice text. Return as a structured table: [paste invoice text]

Compare these two tables — one is a purchase order, one is an invoice from the same vendor. Flag any line items where the invoiced amount exceeds the PO amount by more than 5%, and explain each discrepancy in one sentence.

My AP approval policy: invoices under $5,000 → ops manager, $5,000–$20,000 → CFO, above $20,000 → CFO + CEO co-approval. Given this invoice total of $14,200 from Acme Supplies, draft a short approval request email to the correct approver.

Here are five vendor invoices I received this week [paste data]. Rank them by urgency based on payment due date and flag any that are already overdue as of today, November 15.

Draft a polite follow-up email to [approver name] reminding them that invoice #4821 from Acme Supplies for $8,400 has been pending approval for 3 business days and payment is due in 5 days.

Reality check

Where this gets hard

The walkthrough above works — until your numbers change, the LLM hallucinates, or you have to re-paste everything next month.

No live connection to QuickBooks, NetSuite, or your inbox — every invoice requires a manual download, copy, and paste before the LLM can touch it.

PO matching requires you to export and paste PO data alongside invoice data every single run; the model has no memory of what you pasted last week.

Approval routing logic has to be re-explained in the prompt each time — there's no persistent ruleset the model applies automatically across every invoice.

Nothing gets sent: drafted approval emails sit in the chat window until you manually copy them into your email client and hit send yourself.

No tracking layer exists — once you close the chat, you have no record of which invoices were reviewed, who was notified, or what the model flagged, unless you built your own log.

Batch processing doesn't scale cleanly — paste 15 invoices into one context window and the model starts conflating line items or truncating data; you end up processing one at a time anyway.

Tired of the friction?

Starch runs the whole workflow on live data — no copy-paste, no hallucinated numbers, no re-prompting next month.

See the Starch version →

Starch alternative

The same workflow on Starch

Starch is an agentic operating system — an agent builds the persistent app or automation that handles this workflow continuously against your live accounting and banking data, instead of a prompt you re-run manually each time an invoice lands.

Connect QuickBooks once — Starch syncs your bills, vendors, payments, and invoice entities on a schedule, so every approval workflow starts from live data, not last week's export.

Use the Transaction Insights app to monitor vendor spend patterns and flag invoices where a vendor's charge is materially higher than their historical average — catching exceptions before they reach an approver.

Describe your approval routing rules in plain English and Starch builds the automation: 'When a new bill lands in QuickBooks under $5,000, draft an approval email to the ops manager and send it; flag anything above $20,000 for CFO and CEO review.'

Starch automates follow-up through your connected Gmail or Outlook account — if an approver hasn't responded in 48 hours, it sends a reminder automatically, without you setting a calendar alert.

Use the Task Manager app (currently in beta) to track every in-flight invoice approval by vendor, amount, approver, and due date — with overdue alerts so nothing ages past its payment deadline.

All of this runs continuously. When the next batch of invoices hits QuickBooks, the same agent picks them up, applies your rules, routes approvals, and logs outcomes — without you re-prompting anything.

Get closed-beta access →

Toolkit