# Customer.io Destination

[Customer.io](https://customer.io/) is a popular marketing platform for sending targeted emails and push and SMS notifications to improve customer engagement and overall conversion rate.

## Links

This documentation is split into the following sections:

- [Set up Customer.io destination in RudderStack]({{< ref "destinations/streaming-destinations/customer-io/setup-guide.md" >}})
- [Send events in cloud mode]({{< ref "destinations/streaming-destinations/customer-io/cloud-mode.md" >}})
- [Send events in device mode]({{< ref "destinations/streaming-destinations/customer-io/device-mode.md" >}})

See [RudderStack Connection Modes]({{< ref "destinations/rudderstack-connection-modes.md" >}}) to learn more about sending events in cloud and device modes.

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