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Segments synced from external tools

Read time: 3 minutes
Last edited: Sep 12, 2023
Syncing segments is an Enterprise feature

Syncing segments from external tools is available to customers on an Enterprise plan. To learn more, read about our pricing. To upgrade your plan, contact Sales.


This topic explains how to create segments that sync with an external tool.

A synced segment is a segment that is backed by an external data store. Synced segments can support massive numbers of targets. The exact number is only limited by the data store you configure.

All of the contexts within a synced segment must be of the same context kind. All of the segment's included targets will be associated with that context kind.

Big Segments include synced segments and some list-based segments

You may be familiar with the concept of a "Big Segment," which is a term we previously emphasized in the LaunchDarkly documentation and user interface to describe some segments.

A Big Segment is a segment that is either a synced segment, or a list-based segment with more than 15,000 entries that includes only one targeted context kind. LaunchDarkly uses different implementations for different types of segments so that all of your segments have good performance.

Most of the time, you don't need to keep track of whether your segment is a Big Segment or not. However, you may need to monitor this if you are working with the REST API. Some of the REST API endpoints are specific to Big Segments. To learn more, read Segments in the API documentation.


To use synced segments, you must meet the following prerequisites:

You must configure server-side SDKs to use synced segments

How you need to configure your SDKs depends on what kinds of SDKs you use:

  • Server-side SDKs: You must use an SDK version that supports synced segments.
  • Client-side SDKs: All client-side SDKs support synced segments by default. No additional setup is required.

Configure your SDK: Big Segments

You must properly configure the Relay Proxy to use synced segments with server-side SDKs

How you need to configure the Relay Proxy depends on what kinds of SDKs you use:

  • Server-side SDKs: You must use the Relay Proxy and it must be configured to use synced segments.
  • Client-side SDKs: The Relay Proxy is not required. However, if you do use the Relay Proxy, you must configure it to use synced segments. To learn more, read Using the Relay Proxy.

Updating synced segment details

Synced segments are created by external tools prior to the first sync. When a synced segment is created, the external tool provides the segment's name, key, and description. In some cases, you may want to update the name and description to something more meaningful to your team. Additionally, you may want to add one or more tags to the synced segment.

To update a synced segment's name or description:

  1. Navigate to the segment detail page for the synced segment you want to update.
  2. Select the Settings tab.
  3. Edit the Name, Description, and Tags.
  4. Click Save.

Subsequent targeting syncs will not override any manual changes to the synced segment's name, description, or tags. As with all segment types, you cannot modify a synced segment's key.

Supported external tools

LaunchDarkly supports syncing segments from the following tools:

  • Amplitude