Most published accounts payable invoice processing best practices were written for a payables department and travel badly to a business closing one set of books. Some are excellent at any size: a single point of arrival, a uniqueness check, coding at entry, a visible unapproved list. Others assume people you do not have, and following them produces ceremony rather than control. This page separates the two. It is written for a team of one to fifteen, it says which widely repeated practices do not travel down and why, and it is explicit about the ones we would skip at your size.
The ones that work at any size
One place invoices arrive, so nothing sits in a personal mailbox. A duplicate check at entry. Coding at entry rather than at posting, while the document is in front of somebody. And a visible list of what is unapproved, which does more chasing than a person can.
The ones that do not travel down
A three-tier approval hierarchy, a dedicated exceptions team and a supplier portal all assume headcount. At small scale they add handovers to a process whose problem is waiting, not throughput, and each handover is another place an invoice can stop.
The one to be careful with: automation before documentation
Automating a route that lives in one person's head encodes the folklore. Write it down, run it visibly for a month, then automate what has proved routine. On the worked example on this site, 400 invoices at three touches of six minutes with a 12% exception rate is 134.4 hours a month, $4,300.80 at a $32 loaded rate and $10.75 an invoice.
Questions people ask about accounts payable invoice processing best practices
Is a shared inbox a bad practice?
A shared inbox everybody can see is far better than several personal ones. It becomes a problem when it is the system of record rather than the arrival point, because an inbox has no state.
Should suppliers email invoices or use a portal?
At small scale, email to a single address. A portal is a good answer to a problem you probably do not have yet, and it moves effort onto suppliers who may simply email you anyway.
What about paying by card to skip payables?
It moves the problem to expense reconciliation and removes the approval step entirely, which is usually a downgrade in control dressed as a simplification.