Segments

A segment is a reusable user group defined by shared attributes. Instead of duplicating targeting rules across flags, you define a segment once and reference it.

Why Segments

Imagine you have 50 flags, and a third of them should only be available to Premium users. Without segments, you'd manually configure plan = "premium" on each flag. If the condition changes (e.g., you need to add the "business" plan), you'd have to update all 17 flags.

With a segment, you define the rule once:

{ "field": "plan", "operator": "in", "values": ["premium", "business"] }

Every flag referencing this segment automatically gets the updated rule.

Segment Rules

Segment rules are built on context definitions — the same attributes passed to the SDK. All the same operators and types are supported as for flags. See Contexts.

Rule Combination

Multiple rules within a segment are combined with AND logic — all rules must match for the user to be included.

{
  "name": "Premium RU iOS",
  "rules": [
    { "field": "plan", "operator": "in", "values": ["premium", "business"] },
    { "field": "country", "operator": "eq", "values": ["RU"] },
    { "field": "device", "operator": "eq", "values": ["ios"] }
  ]
}

The user is included only if they have Premium (or Business), are from Russia, and use iOS.

Segments & Environments

Segments are global — available across all environments. But which segments apply to a flag is decided independently at each environment level.

graph LR
    F[Flag: new-checkout]
    F --> DEV[Development<br/>environment]
    F --> PROD[Production<br/>environment]
    DEV --> S1["Segment: Employees"]
    PROD --> S2["Segment: Beta Testers"]

• Development — flag enabled for all employees via a segment.
• Production — «Beta Testers» segment — flag enabled only for them.

Segment Examples

Beta Testers

{
  "name": "Beta Testers",
  "rules": [
    { "field": "userId", "operator": "contains", "values": ["beta-"] }
  ]
}

Includes all users whose userId contains beta-.

Corporate Users

{
  "name": "Corporate Users",
  "rules": [
    { "field": "email", "operator": "contains", "values": ["@company.com"] }
  ]
}

Includes users with email on the @company.com corporate domain.

What's Next

• Flags — flag types and targeting rules
• Activation Rules — how segments integrate into rules
• Environments — where segments are applied