What is ACH payment?

ACH stands for Automated Clearing House, the US electronic funds transfer network that moves money between bank accounts. It is the rails behind direct deposit paychecks, automatic utility payments, and most B2B ACH invoice payments. ACH transactions settle in batches rather than instantly, with standard timing of one to two business days, though same-day ACH is increasingly available.

For receivables, ACH is often the cheapest way to get paid at scale. Per-transaction fees are much lower than credit-card processing, which makes a meaningful difference on larger invoices. Many B2B invoices move by ACH for exactly this reason: the seller keeps more of the face value, and the buyer gets a clean record without cutting a paper check.

The friction on ACH is authorization. The payer has to provide bank details and explicit authorization, and that step is where a lot of invoices stall. Embedding a simple ACH authorization flow into the payment reminder, rather than asking the customer to hunt for account details themselves, is one of the highest-impact changes a business can make to its collection speed.