> ## 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.

# Discarding Events

> Permanently reject invalid or unwanted events

## Usage

<Tabs>
  <Tab title="Node.js">
    ```javascript theme={null}
    subscription.on(async (event) => {
      if (!isValidOrder(event.payload)) {
        await subscription.discard(event.idem, "Invalid order data");
        return;
      }

      await processOrder(event.payload);
      await subscription.ack(event.idem, event.block);
    });
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    async def handle_order(event):
        if not is_valid_order(event.payload):
            await subscription.discard(event.idem, "Invalid order data")
            return

        await process_order(event.payload)
        await subscription.ack(event.idem, event.block)

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

## Parameters

| Parameter | Type     | Required | Description                    |
| --------- | -------- | -------- | ------------------------------ |
| `idem`    | `string` | Yes      | Unique event ID                |
| `reason`  | `string` | No       | Optional reason for discarding |

<Warning>
  Discarded events cannot be recovered. Use defer for temporary failures.
</Warning>