This guide describes other Galileo APIs to monitor and approve ACH transactions, as well as <<glossary:CST>> controls for ACH accounts and transactions.
## Events API webhooks for ACH
Depending on product configuration, ACH events may trigger when an ACH transaction fails. Different events are triggered depending on the direction of the transaction and whether it debits or credits the receiver’s account.
See <a href="ref:api-reference-events-api-transaction-events-index" target="_blank">Transaction Events Index</a> for more information on these events.
|Incoming||`||An incoming ACH credit request fails.<br><br>Set the FACHA parameter to enable this event.||You or Galileo initiate an ACH return.|
|Incoming||`||An incoming ACH debit request fails.<br><br>Set the FACHA parameter to enable this event.||You or Galileo initiate an ACH return.|
|Outgoing||`||An outgoing ACH debit is returned by the external receiver.||If funds have been transferred, Galileo adjusts the funds out of your customer’s account and transfers them to the external bank.|
|Outgoing||`||An outgoing ACH transaction (debit or credit) is returned by the external receiver.<br><br>Set the NTSAA parameter to enable this event.||If funds have been transferred, Galileo adjusts the funds in your customer’s account and, if necessary, transfers funds to the external receiver.|
|Incoming<br>Outgoing||`||An ACH transaction debits funds from the cardholder account.||None|
|Incoming<br>Outgoing||`||An ACH transaction credits funds to the cardholder account.||None|
## External Trans API for ACH
You can choose to approve or deny incoming ACH debit requests via the External Trans API <a href="ref:webhook_ach_debit_post" target="_blank">ACH Debit Webhook</a>. When you reject an incoming debit request, Galileo initiates an ACH return. If you do not respond to an incoming debit request, additional requests will be sent until you respond or the maximum number of attempts has been reached. In the latter case, an ACH return will be initiated.
When a transaction requires approval, it is posted in the <<glossary:CST>> on the _ACH Returns_ page (**System Administration > Other Tools > ACH Returns**). During product setup, the ACDBX parameter must be set to approve or deny ACH returns via the External Trans API.
## Using the CST for ACH
The <<glossary:CST>> has tools to help you manage ACH accounts, transactions, and returns. This section describes ACH controls in the CST _Account_ tab and the _System Administration_ tab.
Some controls may not be available for all users, depending on your administrator’s Roles and Rights settings.
### Account controls
In the CST _Account_ tab, you can manage ACH accounts linked to a customer’s account, view ACH transactions and returns, and manage automated ACH handling. This table describes ACH controls in the CST _Account_ tab.
|**ACH Accounts**||Account > ACH Info||Add, modify, and delete ACH accounts linked to this account.|
|**ACH History**||Account > ACH Info||View the history of outgoing ACH requests for the account, including queued, posted, and returned transactions.|
|**ACH Debit History**||Account > ACH Info||View the history of incoming ACH debit or credit requests for the account, including posted and returned transactions.|
|**ACH Automation Matches**||Account > ACH Info||View ACH transactions that match settings for automated handling and update how a matching transaction is handled in the future.|
|**Payment History**||Account > Account Info||View the payment history for an account, including ACH transactions.|
### System Administration controls
|**Payment Posts & Returns**||System Administration > Other Tools||Review incoming ACH transactions and decide how to handle future ACH transactions with matching program settings.|
|**ACH Returns**||System Administration > Other Tools||Queue for ACH transactions in `|
|**ACH Debit Block Review**||System Administration > Other Tools||View partial matches for ACH stop payment orders. See <a href="doc:ach-at-galileo#ach-stop-payment-orders" target="_blank">ACH stop payment orders</a> for more information.|