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

# Bus

A _bus_ is a logical entity that groups events and links [connectors](connector.md), which send events to the bus from external sources, with [rules](rule.md) that process events and deliver them to [targets](rule.md#target).

An event is a JSON object delivered to the bus in one of these ways:
* Via a connector.
* Via the [EventService/Put](../../eventrouter/api-ref/grpc/Event/put.md) gRPC API call. You can use the API to deliver user events.

For more information about sending events to a bus, see [Sending events to the bus](sending-events.md).

An event is considered processed when all targets of all triggered rules return a successful response, or when the event is moved to a dead-letter queue.