Ben Rometsch edited this page Nov 29, 2018 · 1 revision


If a project uses Bullet Train to identify their users, we actually get a lot of data that could be used to serve feature flags more intelligently.

We would enable Bullet Train administrators to create a new Segment, and then define the rules that define which users are added to that segment. As the Bullet Train clients identify users with traits, rules can be written around those traits to define the segment.

The segments would be defined by one or more rules that combine together. For example, if trait X exists AND trait Y > 5.

Flags can then be defined/overriden based on these segments. So for example, if a user is in a particular segment, and that segment has a different feature flag state to the default, we would serve the segment flag instead.

We would provide an API that would allow third parties to get read access these segmented users.

Use Cases


Users would be able to query and keep track of how many users belong in a certain segment, this would allow you to monitor users segments and treat them like goals.

Power Users Segment

The client keeps track of how often the user opens the app and keep the number in an INT trait. The Power Users segment is defined by identities that have that number greater than 10.

Gmail Users Segment

The client sends the email address as part of the identity. The rule in this case would be emailAddress CONTAINS ‘’. The application can then have specific feature flags to enable GMail related features.

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