# Flex developer documentation

Twilio Flex is a digital engagement center for sales and service that gives developers control over the customer experience with the speed and flexibility of the cloud. This documentation provides reference materials and learning resources for customizing a Flex instance with code. For configuration and usage guidance, see the [Administrator Guide](/docs/flex/admin-guide) and [End User Guides](/docs/flex/end-user-guide).

## Working with Flex

Flex provides a [range of user interfaces](/docs/flex/admin-guide/core-concepts/flex-ui) for your agents and customers, a [visual flow builder](/docs/flex/admin-guide/tutorials/ivr), and [pre-built routing logic](/docs/flex/admin-guide/core-concepts/routing) that you can customize. With Flex, you can:

* Add channels like [Voice](/docs/flex/developer/voice) and [Conversations](/docs/flex/conversations) (requires [Flex UI 2.x](/docs/flex/release-notes/flex-ui-release-notes-for-v2xx)) for configuration options.
* Create [engagement workflows](/docs/flex/admin-guide/tutorials/queues-and-skills-based-routing) and [intelligent routing](/docs/flex/developer/routing).
* [Gain operational insight](/docs/flex/developer/insights) by providing stakeholders with pre-built dashboards for various customer-agent interactions, setting up email-based alerting, and scheduling report delivery with email.
* Integrate Flex with your [IdP (Identity Provider)](/docs/flex/admin-guide/setup/sso-configuration) and [manage user authentication](/docs/flex/admin-guide/setup/flex-ui-users).
* Securely [embed Flex](/docs/flex/admin-guide/setup/secure-iframe) in your application.

## What's next?

* Learn how to [update the Flex UI programmatically](/docs/flex/developer/ui/overview-of-flex-ui-programmability-options) or dive into the [Flex UI Reference documentation](https://assets.flex.twilio.com/docs/releases/flex-ui/latest/)
* Explore how to [build custom Flex plugins](/docs/flex/quickstart/getting-started-plugin)
* Learn how to [set up and administer Flex](/docs/flex/admin-guide)
* Learn how to use Flex with the [End User Guides](/docs/flex/end-user-guide)