Launched: Segments, Separate Your Users Into Reusable Segments


One of the core benefits of the LaunchDarkly feature management platform is the ability to target end-users on a granular level. This means you not only have control over when a feature is ‘on’, but can decide who will see/experience it. Teams using LaunchDarkly use targeting rules to perform beta releases, canary launches, test in production, or even manage entitlements like tiered pricing structures.

We’ve gotten feedback that teams often want to target the same group of people for multiple different features. Unfortunately this meant building that list of targeting rules each time for each flag. So to make that process easier, we’ve introduced a new feature called Segments that allow you to build a list of targeting rules that can be used for different feature flags.

Segments are great for dark launchers who are targeting the same group of users for different features. This can be users of a particular technology (e.g. all of your Gmail users), a long-lived beta testing group, a particular department within your organization–you get the idea. Segments makes it easier to consistently reach particular groups that you work with over time. To use this new feature, existing LaunchDarkly customers should make sure you update your SDK (you can read more about that here).

How does this work?

In this example, I describe a set of users called Gmail Users with email addresses ending with

Then, in a feature flag called Use Rich Formatting for Email I add a rule to include Gmail Users in the list of users receiving this feature flag value.

In another feature flag called Encourage Users to Switch to Gmail I add a targeting rule to  exclude Gmail Users.

That’s all there is.

How are Segments different than Prerequisites?

Our more advanced dark launchers might have noticed that segments appear very similar to prerequisites. Just remember: segments allow you to target users by key or attributes, and prerequisites represent a dependency on a flag value served to a user.

How do I get this new feature?

If you created an account starting March 1, 2018, you have already Segments. Congratulations! If you joined before that, then use of Segments requires that you update your server-side SDKs (you can read more about that here). For specific requirements, see our documentation for building user segments. Contact us at if you think your application is ready to handle Segments.

Andrew is a software engineer at LaunchDarkly. He has worked on every part of the computer except the chime. He has a passion for building tools that make developing great software (and hardware) easier for himself and his teammates. Andrew has a B.A. in Mathematics and Computer Science from Swarthmore College in Pennsylvania.