> ## Documentation Index
> Fetch the complete documentation index at: https://launchdarkly-preview.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Twilio Segment schema reference

> This topic explains the different event kinds for Twilio Segment Data Export destinations.

> For the complete documentation index, see [llms.txt](/llms.txt). For the full documentation snapshot, see [llms-full.txt](/llms-full.txt).

## Overview

This topic explains the different event kinds for Twilio Segment Data Export destinations. The JSON schemas for Twilio Segment are formatted differently than LaunchDarkly's. The `index`, `identify`, and `summary` event kinds are **not available** in Twilio Segment Data Export destinations, and other events are exported with different labels.

To learn more about the Twilio Segment destination, read [Twilio's Segment documentation](https://www.twilio.com/docs/segment).

There are four different event kinds exported to Twilio Segment. They are:

* [Feature events](#feature-events): This event is emitted when a feature flag is evaluated.
* [Click events](#click-events): This event is emitted when an end user clicks on a CSS selector for which they have configured a metric in an experiment.
* [Page view events](#page-view-events): This event is emitted when an end user loads a page associated with an experiment metrics.
* [Custom events](#custom-events): This event is emitted when LaunchDarkly SDK sends a `custom` event. LaunchDarkly no longer supports `alias` events for SDKs upgraded to contexts. LaunchDarkly continues to support sending and receiving alias events for older SDK versions. For a list of SDKs that still support `alias` events, read [Aliasing users](/sdk/features/aliasing-users).

### Additional properties

Twilio Segment events include additional information about different LaunchDarkly properties. These properties are included in all event kinds.

These properties are:

\| Property name

| Property details |
| - |

\| --- |
\| <code> event </code>

\| The event kind. This field maps onto [Twilio Segment's event field](https://www.twilio.com/docs/segment/connections/spec/track). |
\| <code> environment </code>

\| The LaunchDarkly environment ID, also called the client-side ID, corresponding to the event. |
\| <code> project </code>

\| The LaunchDarkly project key corresponding to the event. |
\| <code> key </code>

\| The flag key corresponding to the event. In the case of Experimentation events, this will be the metric key for the experiment. |
\| <code> userId </code>

\| The key of the user object or user context kind associated with the emitted event. For example, in client-side SDKs, this is the key of the currently identified user. This field maps onto [Twilio Segment's userId field](https://www.twilio.com/docs/segment/connections/spec/track). |
\| <code> contextKeys </code>

\| An object of <code>contextKind: contextKey</code> pairs for each context kind in the event. |

## Feature events

This table explains `feature` event properties:

\| Property name

| Description |
| - |

\| --- |
\| <code> value </code>

\| The value of the evaluated flag. |
\| <code> flagVersion </code>

\| The version of the evaluated flag. |
\| <code> inExperiment </code>

\| <code>true</code> if this flag evaluation was allocated to an experiment. <br /> To learn more, read Allocating experiment audiences]\(/home/experimentation/allocation). |
\| <code> reasonKind </code>

\| The evaluation reason for the flag. <br /> To learn more, read [Evaluation reasons](/sdk/concepts/evaluation-reasons). |
\| <code> prereqOf </code>

\| Set to another flag’s key if this flag evaluation was only performed in order to determine whether the prerequisite values were met for the indicated flag. <br /> To learn more, read [Flag prerequisites](/home/flags/prereqs). |
\| <code> default </code>

\| Indicates whether the flag value was the result of the default variation being evaluated. |
\| <code> variation </code>

\| The variation of the flag requested. The SDK stores flag variation values in an array. This value corresponds to the index of the variation the array. Boolean flags show as <code>0</code> or <code>1</code> for <code>true</code> and <code>false</code>. For other flags, the array index starts at <code>0</code> for their different variations. |
\| <code> variationName </code>

\| The evaluated variation's name, if it exists. If the evaluated variation doesn't have a name, this field doesn't appear. |

## Click events

This table explains `click` event properties:

\| Property name

| Description |
| - |

\| --- |
\| <code> url </code>

\| The URL from which a user context triggered a flag evaluation. |
\| <code> selector </code>

\| The CSS selector corresponding to the <code>click</code> event. |

## Page view events

This table explains `page view` event properties:

\| Property name

| Description |
| - |

\| --- |
\| <code> url </code>

\| The URL from which a user context triggered a flag evaluation. |

## Custom events

Custom events contain the properties listed under [Additional properties](#additional-properties).

This table explains `custom` event properties not listed in that section:

\| Property name

| Description |
| - |

\| --- |
\| <code> metricValue </code>

\| The numeric value of a metric if it is specified in the event. If no metric value was provided, this field doesn't appear. |