The ACHeck21 API makes it possible to send and receive money between U.S.A. bank accounts. It does this by using standards implemented by banks and the Federal Reserve for transferring money called ACH and Check21. For a more in-depth discussion of these standards see our ACH/Check21 Primer.


You can start using the API in a sandbox environment right-away by signing up for an account on our Sign up page. In the sandbox environment, no money is actually transferred. The payment settlements are simulated.

When you are ready to perform real transactions you will need to contact us to and sign an agreement. You will also need to obtain or already have a special bank account called an ACH clearing account. See the Moving from the sandbox into production section below for more details.

What you can (and cannot) do with the API

Typical use-cases for the API

  • Accept online payments that directly debits a user's bank account
  • Disburse commissions directly to affiliate's bank accounts
  • Direct debit/credit in an automated account receivables/payables accounting application.
  • Direct deposit employee payroll.
  • Money transfer applications
  • Backend for automated check capture solutions. Utilities, charities, etc.

The most notable restriction to what is possible is that you can only perform transactions between your own account (which we will have on record) and another party.
This means you can't perform direct money transfer between two third-parties. However, you can perform an indirect transfer by acting as an intermediary. For example, debit one party into your own account, then credit another from your own account.

Moving from the sandbox into production

Once you are ready to move from the sandbox environment into production, your bank account involved in the each transaction will need to be a special account owned by your organization called an ACH clearing account. The clearing account is different from a typical consumer bank account. It's not difficult to obtain one of these accounts but there is an underwriting process that involves a credit and background check. We are more than happy to help you obtain one of these if you don't already have one.