[Yandex Cloud documentation](../../../index.md) > [Yandex API Gateway](../../index.md) > [Step-by-step guides](../index.md) > Creating a trigger > Creating a timer

# Creating a timer that sends messages to WebSocket connections

Create a [timer](../../concepts/trigger/timer.md), i.e., a trigger to send messages to [WebSocket connections](../../concepts/extensions/websocket.md) on schedule.

## Getting started {#before-you-begin}

To create a trigger, you will need:

* API gateway. Messages will be sent to WebSocket connections accessing the API gateway at the path specified in the trigger settings. If you do not have an API gateway, [create one](../api-gw-create.md).

    {% note info %}

    The trigger does not call the API gateway when sending messages to WebSocket connections.

    {% endnote %}

* [Service account](../../../iam/concepts/users/service-accounts.md) with the `api-gateway.websocketBroadcaster` role. If you do not have a service account, [create one](../../../iam/operations/sa/create.md).

## Creating a trigger {#trigger-create}

{% note info %}

The trigger is initiated within five minutes after it is created.

{% endnote %}

{% list tabs group=instructions %}

- Management console {#console}

    1. In the [management console](https://console.yandex.cloud), select the folder where you want to create a trigger.

    1. Navigate to **API Gateway**.

    1. In the left-hand panel, select ![image](../../../_assets/console-icons/gear-play.svg) **Triggers**.

    1. Click **Create trigger**.

    1. Under **Basic settings**:

        * Enter a name and description for the trigger.
        * In the **Type** field, select `Timer`.
        * In the **Launched resource** field, select `API gateway`.

    1. Under **Timer settings**:

        * In the **Cron expression** field, specify a schedule for sending messages to WebSocket connections as a [cron expression](../../concepts/trigger/timer.md#cron-expression).
        * Optionally, in the **Payload** field, specify the message to send to WebSocket connections if the timer fires in the `payload` field. The data type is a string up to 4,096 characters long.

    1. Under **API gateway settings**:
       * In the **API gateway** field, select the API gateway.
       * In the **Path** field, specify the path in the OpenAPI specification. Messages will be sent through WebSocket connections established using this path.
       * In the **Service account** field, select the [service account](../../../iam/concepts/users/service-accounts.md) to send messages to WebSocket connections.

    1. Click **Create trigger**.

- CLI {#cli}

    If you do not have the Yandex Cloud CLI yet, [install and initialize it](../../../cli/quickstart.md#install).

    The folder used by default is the one specified when [creating](../../../cli/operations/profile/profile-create.md) the CLI profile. To change the default folder, use the `yc config set folder-id <folder_ID>` command. You can also specify a different folder for any command using `--folder-name` or `--folder-id`. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.

    To create a trigger that sends messages to WebSocket connections, run this command:

    ```bash
    yc serverless trigger create timer \
      --name <timer_name> \
      --cron-expression '<cron_expression>' \
      --payload <message> \
      --gateway-id <API_gateway_ID> \
      --gateway-websocket-broadcast-path <path> \
      --gateway-websocket-broadcast-service-account-id <service_account_ID>
    ```

    Where:

    * `--name`: Timer name.
    * `--cron-expression`: Schedule for sending messages to WebSocket connections as a [cron expression](../../concepts/trigger/timer.md#cron-expression).
    * `--payload`: Message to send to WebSocket connections if the timer fires. The string length must not exceed 4,096 characters.

    * `--gateway-id`: API gateway ID.
    * `--gateway-websocket-broadcast-path`: Path in the OpenAPI specification. Messages will be sent through WebSocket connections established using this path.
    * `--gateway-websocket-broadcast-account-id`: Service account ID with permissions to send messages to WebSocket connections.

    Result:

    ```text
    id: a1s5msktijh2********
    folder_id: b1gmit33hgh2********
    created_at: "2023-08-04T15:19:15.353909857Z"
    name: timer
    rule:
      timer:
        cron_expression: 5 10 ? * * *
        payload: <message>
        gateway_websocket_broadcast:
          gateway_id: d4eofc7n0mh2********
          path: /
          service_account_id: aje3932acdh2********
    status: ACTIVE
    ```

- API {#api}

  To create a timer, use the [create](../../triggers/api-ref/Trigger/create.md) REST API method for the [Trigger](../../triggers/api-ref/Trigger/index.md) resource or the [TriggerService/Create](../../triggers/api-ref/grpc/Trigger/create.md) gRPC API call.

{% endlist %}

## Checking the result {#check-result}

Check that the trigger operates correctly. Do it by viewing the [API gateway logs](../api-gw-logs.md) that present information about its incoming requests.

## Useful links {#see-also}

* [Timer that invokes a Cloud Functions function](../../../functions/operations/trigger/timer-create.md)
* [Timer that invokes a Serverless Containers container](../../../serverless-containers/operations/timer-create.md)