> For the complete documentation index, see [llms.txt](https://docs.elemitech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.elemitech.com/utility-functions/handling-notifications-callbacks/callback-events.md).

# Callback Events

Depending on the workflow (collection, invoice generation/payment, disbursement etc) being used, the gateway will send appropriate events to the appropriate callback URLs. For every workflow type, the applicable events are described below;

### Collections

<table><thead><tr><th width="218">Event</th><th width="176">Transaction Status</th><th>Description</th></tr></thead><tbody><tr><td>request.failed</td><td>FAILED</td><td>Request failed and could not be processed by the gateway. Failure reason is part of the callback payload</td></tr><tr><td>transaction.charges</td><td>PENDING</td><td>Communicates success of the first collection leg (initialization) and the charges to be levied. The collection confirmation request should be sent after this event is received</td></tr><tr><td>transaction.processing</td><td>PROCESSING</td><td>Notifies the merchant that transaction processing is ongoing. Returns mobile money instructions (when payment method is MOBILE_MONEY) or the card payment URL (when payment method is CARD)</td></tr><tr><td>transaction.failed</td><td>FAILED</td><td>The gateway tried to process the transaction but failed e.g. insufficient balance on the account. Failure reason is part of the callback payload</td></tr><tr><td>transaction.completed</td><td>COMPLETED</td><td>The gateway processed the collection successfully.</td></tr></tbody></table>

### Invoices (Generation and Payment)

<table><thead><tr><th width="180">Event</th><th>Description</th></tr></thead><tbody><tr><td>request.failed</td><td>Request failed and could not be processed by the gateway. Failure reason is part of the callback payload</td></tr><tr><td>invoice.generated</td><td>Event sent at successful generation of the invoice. Details of the invoice would be shared as part of the payload</td></tr><tr><td>invoice.paid</td><td>Event sent when the invoice is paid for. Part of the payload is the reference for the collection that fulfilled the invoice</td></tr></tbody></table>

### Payouts/Disbursements

<table><thead><tr><th width="218">Event</th><th width="175">Transaction Status</th><th>Description</th></tr></thead><tbody><tr><td>request.failed</td><td>FAILED</td><td>Request failed and could not be processed by the gateway. Failure reason is part of the callback payload</td></tr><tr><td>transaction.failed</td><td>FAILED</td><td>The gateway tried to process the transaction but failed. Failure reason is part of the callback payload</td></tr><tr><td>transaction.completed</td><td>COMPLETED</td><td>The gateway processed the payout successfully.</td></tr></tbody></table>