AI agents for finance · Part 3 of 14
Build or buy an AI agent for accounts payable
Your accounting system’s own agent, an AP platform’s agents, or your own build: what each charges for, who holds the money and the approvals, and what to ask before you sign.
The short version
You can switch on the agent in your accounting system, use the agents in an AP platform, or build your own on your accounting system’s API. They charge by different units: credits per invoice and line, a price per user, a monthly plan, or a quote. Then find out, for each route, who holds the supplier records, where the approval policy applies and which system moves the money. Ask the five questions below before you sign.
What you pay for
Your accounting system’s agent works where your suppliers and ledger already are. An AP platform’s agents work inside a product that also pays your suppliers. Your own build puts a model between your accounting system’s API and your bank. Each charges by a different unit.
Your accounting system’s agent
Business Central’s Payables Agent
- Its agent
- reads PDF invoices and drafts the bills
- You pay
- 50 Copilot Credits an invoice, plus 5 a line; the first 50 invoices free in trial mode
An AP platform’s agents
Ramp
- Its agent
- codes lines, suggests approvals, pays card-eligible invoices
- You pay
- on Plus: $15 a user a month, plus a platform fee by team size
BILL
- Its agent
- codes lines: its Invoice Coding Agent
- You pay
- with Team, $65, or Corporate, $89, a user a month; not with Essentials, $49
Tipalti
- Its agent
- lists AI agents for bill approvals, invoice scan, PO matching
- You pay
- AP plans from $99 a month
Stampli
- Its agent
- Billy, which its page says “Does 89% of finance work”
- You pay
- on request: no price shown
Your own build
Your accounting system’s API
- Its agent
- whatever you build on the API and your bank
- You pay
- the model’s use and your team’s time; no list price
Microsoft prices its agent by the invoice: 50 Copilot Credits to process one, plus 5 for each line, so a three-line invoice uses 65. Its setup page suggests the free trial, 50 invoices, to estimate your own use. The platforms charge per user or per plan, so ask whether everyone who approves a bill counts as a user. For your own build there is no list price: the model’s use and your team’s time are the cost, and so are the checks you would otherwise buy.
Who holds the money
The price is one question. The other is where four things live in each route: the supplier records with their bank details, the approval policy, the payment itself, and the record of what happened.
Your system’s agent
Such as Business Central’s.
- Supplier records
- your accounting system
- Approval policy
- its approval workflows, separate from the agent
- The payment
- your bank, as today: the agent doesn’t pay
- The record
- the agent’s timeline of each step, and your ledger
An AP platform
Such as Ramp or BILL.
- Supplier records
- the platform, synced with your accounting system
- Approval policy
- the platform’s approval rules, on every bill
- The payment
- the platform: ACH, card, check or wire
- The record
- the platform’s history. Ask what you can export.
Your own build
The API, a model, your bank.
- Supplier records
- your accounting system
- Approval policy
- yours to build, outside the agent
- The payment
- your bank or payment provider, by your code
- The record
- yours to build, with the reason for each action
The approval policy matters most. A platform applies its approval rules to every bill, whoever prepared it, and Ramp’s Plus plan lists “Payment release approvals” as well. In your own build, the instructions you give the agent are not an approval policy: put the check in the code that sends the payment, where the agent can’t skip it. Support part 3 asks the same of any vendor, in its second question.
What to ask before you sign
Ask support part 3’s general questions too. These five are accounts payable’s own.
Can the agent release a payment, or only prepare one?
And who can change that? Ask to see the setting in the product’s admin, and who holds the permission to switch it on.
What happens when a supplier’s bank details change?
Who confirms the change, and how: a call to a number already on file, or a reply to the email that asked for it? Part 9 sets the rule.
Does the agent act under its own user and permissions?
Business Central’s agent has its own user, with a permission set limited to processing vendor invoices. Ask any vendor for the same, so you can see and limit what the agent touches.
What does it cost at your volume, and when credits run out?
Price it on last month’s invoices. When credits return after running out, Business Central’s agent works through the invoices that piled up, and Microsoft warns this can use a large part of the new credits quickly.
Can you export the record of every action, with its reason?
Who did what, when, and under which rule, for each invoice, in a form your auditor can read. Part 14 covers what to keep.
Next in this series
Part 4, your approval policy written for an agent, comes next. See all 14 parts.
Where Himmel fits
Himmel is the check outside the agent in the third column: your code asks Himmel before it sends a payment, and Himmel answers from your written approval policy, with the clause it applied.
Sources
- Microsoft Learn, Business Central’s consumption-based billing: the Payables Agent’s credits per invoice and per line, read on 25 October 2026.
- Microsoft Learn, “Set Up Payables Agent in Business Central”: trial mode, credits running out, the agent’s user and permission set, dated 2 October 2026, read on 25 October 2026.
- Microsoft Learn, “Payables Agent Frequently Asked Questions”, dated 2 October 2026, read on 25 October 2026.
- Ramp, pricing, and Ramp, “Accounts Payable Software”, read on 25 October 2026.
- BILL, pricing, read on 25 October 2026.
- Tipalti, “Pricing and Plans”, read on 25 October 2026.
- Stampli, “Pricing”, read on 25 October 2026.