Feature Flags

Runtime feature toggles with percentage rollouts and user targeting.

Flag Types

Boolean: On/off

{
  "key": "dark-mode",
  "flag_type": "boolean",
  "enabled": true,
  "default_value": "false"
}

Variant: Multi-option (A/B testing)

{
  "key": "checkout-flow",
  "flag_type": "variant",
  "enabled": true,
  "default_value": "control",
  "variants": [
    {"value": "control", "weight": 50},
    {"value": "variant-a", "weight": 50}
  ]
}

Rollout

Percentage-based gradual rollout:

{
  "key": "new-ui",
  "enabled": true,
  "rollout_percentage": 25,
  "rollout_attribute": "user_id"
}

Users assigned deterministically (hash of flag key + user_id). Same user always gets same result.

Targeting

Individual targeting:

{
  "individual_targets": {
    "included_keys": ["user123", "user456"],
    "excluded_keys": ["user789"]
  }
}

Attribute rules:

{
  "targeting_rules": [{
    "attribute": "plan",
    "operator": "equals",
    "values": ["premium", "enterprise"],
    "value": "true"
  }]
}

Operators: equals, not_equals, contains, in_list, greater_than, less_than, matches_regex, in_segment

Segments: Reusable targeting groups

{
  "targeting_rules": [{
    "operator": "in_segment",
    "values": ["beta-users"],
    "value": "true"
  }]
}

Evaluation

POST /api/v1/projects/{slug}/environments/{env}/flags/{key}/evaluate
{
  "context": {
    "user_id": "user123",
    "email": "[email protected]",
    "plan": "premium"
  }
}

Response:

{
  "enabled": true,
  "value": "true",
  "reason": "RULE_MATCH"
}

Evaluation order:

1. Individual targets (included → excluded)
2. Targeting rules (first match wins)
3. Percentage rollout
4. Default value

History

Tracks: created, updated, deleted, toggled (enable/disable)

SSE Streaming

Real-time flag updates:

GET /api/v1/projects/{slug}/environments/{env}/flags/stream

Server-sent events pushed when flags change.

API

GET    /api/v1/projects/{slug}/environments/{env}/flags
POST   /api/v1/projects/{slug}/environments/{env}/flags
GET    /api/v1/projects/{slug}/environments/{env}/flags/{key}
PATCH  /api/v1/projects/{slug}/environments/{env}/flags/{key}
DELETE /api/v1/projects/{slug}/environments/{env}/flags/{key}
PUT    /api/v1/projects/{slug}/environments/{env}/flags/{key}/toggle

Limits

• Personal (Free): 10 flags per environment
• Starter ($5/user): Unlimited flags