An integrated accounts payable system is sold on the word integrated, which covers everything from a nightly file export to a live two-way connection, and the difference between those decides whether you have one system or two that need reconciling. There are four connections that matter for a small business, they carry different risks, and each has a specific question worth asking before signing. This page is the four, what good looks like for each, and the failure question that reveals more than any demonstration, because integrations are judged on what happens when they break rather than on what happens when they work.
The four connections that matter
Into the ledger, so approved invoices post without re-entry. To the bank, so payment runs are not re-keyed. To purchase orders, so matching has something to match against. And to your document store, so the invoice image stays with the record.
What good looks like
For each: does it write automatically or produce a file somebody imports, does it write once or duplicate on retry, and does it tell you when it fails. A connection that silently drops a record is worse than a manual process, because nobody is looking.
The failure question
Ask what happens when the write fails: does the invoice stay in a visible failed state, does somebody get told, and can it be retried without creating a duplicate. Vendors demonstrate the success path; the failure path is what you will live with. 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, $10.75 an invoice and $51,609.60 a year.
Questions people ask about integrated accounts payable system
Is a nightly file export good enough?
It works and it creates a window where the two systems disagree, which somebody has to reconcile. At low volumes that is tolerable; at higher ones it becomes a daily task nobody owns.
Should the payables system or the ledger be the master?
The ledger, for the accounting record. The payables system holds the workflow state. Confusion about which is authoritative is the commonest source of trouble in a two-system setup.
What about integrating with purchase orders we do not have?
Then that connection is moot and two-way matching is your ceiling, which is fine if chosen deliberately.