> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ensync.cloud/llms.txt
> Use this file to discover all available pages before exploring further.

# Deferring Events

> Postpone event processing with retry logic

## Usage

<Tabs>
  <Tab title="Node.js">
    ```javascript theme={null}
    subscription.on(async (event) => {
      try {
        await processPayment(event.payload);
        await subscription.ack(event.idem, event.block);
      } catch (error) {
        // Defer for 5 seconds
        await subscription.defer(event.idem, 5000, "Temporary error");
      }
    });
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    async def handle_payment(event):
        try:
            await process_payment(event.payload)
            await subscription.ack(event.idem, event.block)
        except Exception as error:
            # Defer for 5 seconds
            await subscription.defer(event.idem, 5000, "Temporary error")

    subscription.on(handle_payment)
    ```
  </Tab>
</Tabs>

## Parameters

| Parameter | Type     | Required | Description                   |
| --------- | -------- | -------- | ----------------------------- |
| `idem`    | `string` | Yes      | Unique event ID               |
| `delayMs` | `number` | Yes      | Delay in milliseconds         |
| `reason`  | `string` | No       | Optional reason for deferring |

<Note>
  Deferred events return to the queue after the delay. Any of your client instances sharing the same appKey can receive them.
</Note>