This article describes a use case. We have not delivered an engagement to a CPA firm. What follows is what we see of the profession, and what public sources say.

What a CPA firm should prepare

A CPA firm has no federal e-invoicing date to meet, so accounting firm automation starts with a plain list: which clients get invoicing rules from large customers, federal agencies or Europe, what each one must send, and by when. The requirement reaches small clients through someone else, one client at a time.

A mandate that never came

Elsewhere, governments set the date. France has required every business to be able to receive electronic invoices since September 1, 2026, according to Service-public.fr. A CPA firm in the US has no such day on its calendar: as of 2026, no B2B e-invoicing mandate exists in US law.

The reason is structural. The Federal Reserve Bank of Minneapolis put US adoption at 25 percent in its 2016 paper, comparable to Europe at the time. It noted that countries with a value added tax have a natural incentive to push e-invoicing, and that the US lacks this incentive. What moved adoption instead was large companies trying to run their payables and receivables more efficiently.

That paper is ten years old, and the figure has surely moved. The mechanism it describes is what matters here.

Who decides for a small client

With no statute to point to, the rule comes from whoever pays the invoice. The Fed said so plainly:

“Smaller companies typically have little control over the use or non-use of e-invoicing, as their larger trading partners or other customers dictate the invoicing method.” — Federal Reserve Bank of Minneapolis, U.S. Adoption of Electronic Invoicing

So the pressure arrives unevenly, from three directions:

A large customer moves its suppliers onto its own portal, with its own format and its own rules for what gets paid.
A federal agency asks its vendors to bill through a government system, such as the Treasury’s Invoice Processing Platform, offered at no cost to agencies and their vendors.
A client selling into Europe meets rules written for a VAT system. The European Commission says digital reporting will affect cross-border B2B transactions from July 1, 2030, and France shows that a member state can move first.

None of these looks like a compliance deadline from inside a CPA firm. It looks like a client calling to ask why an invoice was rejected.

The list nobody keeps

A national mandate is at least the same for everyone. Here, each client has its own situation, and the firm learns about it late, usually when a payment stalls.

The Fed also pointed out that portals do not necessarily make the work more automatic. A small business may enter the same invoice by hand on a customer’s site, send a PDF to another and mail paper to a third. Then the books have to agree with all of it.

The ledger and the tax software do their jobs on what reaches them. Neither one holds the answers a partner would want before busy season:

Which clients bill a customer or an agency that dictates the format?
Which ones sell into Europe, and in which countries?
Whose invoices were rejected or sent twice, and who noticed?
Who has never been asked any of these questions?

Today that list lives in a spreadsheet or in a senior person’s head, if it exists at all. We have written about the documents a firm has to chase. This is the same kind of work, one level up: not a missing document, but a missing picture of the client base.

What an agent could take on

Nothing that counts as advice. Only keeping that picture current.

Keeping track, client by client, of who bills whom and under which requirement, from what already reaches the firm.
Preparing the questions and reminders, so a staff member only has to read them and decide.
Flagging an invoice that shows up twice or was rejected, without settling the matter itself.

What would not move: the analysis, the tax position, the choice of a system, the signature and the advice. An agent that told a client how to treat VAT in another country would be doing exactly what it must not do. More on the scope is on our page on AI agents for CPA firms.

Why we put this in the conditional

Because we have not delivered this to a CPA firm, and saying otherwise would be false.

What we do know how to do is proven elsewhere. Each agent is custom-built and installed at the client’s office. Files stay on the client’s machines, and only the text a task needs is sent to the AI model. What that would look like at a US firm is still to be built, and it would start by looking at a real client list.

The cost is public: from $1,700 per agent, then $170 per month. See pricing for a custom agent.

Engagements we have actually delivered and use cases are clearly told apart in our case studies and use cases by industry.

No US e-invoicing deadline. The work arrives anyway.