[Yandex Cloud documentation](../../../index.md) > [Yandex Serverless Integrations](../../index.md) > [Concepts](../index.md) > EventRouter > Connector

# Connector

A _connector_ is a customizable component made to receive events from external sources and forward those events to a [bus](bus.md).

Supported sources:

* [Timer](#timer)
* [API EventRouter](#from-api)
* [Yandex Data Streams](../../../data-streams/index.md)
* [Yandex Message Queue](../../../message-queue/index.md)


## Timer {#timer}

Timer is a source type that triggers scheduled event generation. The schedule is set in cron expression format. By default, cron expression uses [UTC+0](https://en.wikipedia.org/wiki/Coordinated_Universal_Time), but you can specify a different time zone in timer settings.

If timer settings do not specify the data to provide to the bus, nothing is sent to the input of the [target](rule.md#target) specified in the [rule](rule.md).

To learn more about the cron expression format, see [Cron expressions in Serverless Integrations](../cron.md).


## EventRouter API {#from-api}

The EventRouter API is a source type that enables using the [EventRouter API](../../api-ref/eventrouter/authentication.md) to [send](sending-events.md) user events to the bus.

To send events [via an EventRouter API connector](../../operations/eventrouter/bus/data-send.md), use the `EventService/Send` gRPC API [call](../../eventrouter/api-ref/grpc/Event/send.md) or the `yc serverless eventrouter send-event` Yandex Cloud CLI [command](../../../cli/cli-ref/serverless/cli-ref/eventrouter/send-event.md).

As opposed to sending messages [directly to the bus](../../operations/eventrouter/bus/data-put.md), the EventRouter API connector enables you to:
* Grant users and [service accounts](../../../iam/concepts/users/service-accounts.md) granular permissions to send events via the specified connector.
* Terminate event sending by [stopping](../../operations/eventrouter/connector/stop.md) the connector.
* Group events before sending them to the bus.