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

# Nack messages

> Nack messages in a Sequin Stream

## Request parameters

<ParamField path="consumer_id_or_name" type="string" required>
  The ID or name of the Sequin Stream.
</ParamField>

<ParamField body="ack_ids" type="string[]" required>
  An array of `ack_id` values to nack.

  Each message returned by the [`/receive` endpoint](/reference/sequin-stream-api/receive) contains an `ack_id` that you can use to `nack` the message.
</ParamField>

<RequestExample>
  ```shell theme={null}
  curl --request POST \
    --url https://api.sequinstream.com/api/http_pull_consumers/orders-pull-consumer/nack \
    --header 'Authorization: Bearer YOUR_API_TOKEN'\
    --header 'Content-Type: application/json' \
    --data '{
      "ack_ids": ["MTYyeJ7abUjl1pO", "MTYyeJ7abUjl1pP"]
    }'
  ```
</RequestExample>

<ResponseExample>
  ```json 200 OK theme={null}
  { "success": true }
  ```
</ResponseExample>