Flag types, variants, targeting rules, evaluation engine, and OpenFeature compatibility.

Feature Flags

Kaiten provides a full-featured feature flag engine with OpenFeature (OFREP) compatibility, CEL-based targeting, and rollout strategies.

Flag Types

Type	Variants contain	Example
`boolean`	`true` / `false` values	"Enable dark mode"
`string`	Arbitrary string values	`"red"`, `"blue"`, `"control"`
`number`	Numeric values	`0`, `1`, `42`
`object`	JSON objects	`{"theme": "festive", "discount": 15}`

Anatomy of a Feature Flag

{
  "name": "Promo Banner",
  "slug": "promo-banner",
  "type": "object",
  "enabled": true,
  "variants": [
    {"name": "disabled", "value": {"enabled": false}},
    {"name": "festive", "value": {"enabled": true, "message": "🍣 Free miso!"}}
  ],
  "defaultVariant": {"type": "basic", "value": "disabled"},
  "targetingRules": [
    {
      "type": "basic",
      "rule": "tenantSlug == \"sakura-tokyo\"",
      "variant": "festive"
    }
  ]
}

Default Variant Strategies

The defaultVariant determines what happens when no targeting rule matches:

Strategy	Description
`basic`	Always returns a specific variant
`rolloutPercentage`	Distributes traffic across variants (e.g. 50/50)

Rollout Percentage Example

{
  "type": "rolloutPercentage",
  "value": {
    "rolloutPercentage": {
      "distribution": {"on": 30, "off": 70}
    }
  }
}

Targeting Rules (CEL)

Targeting rules use CEL (Common Expression Language) to match context variables:

tenantSlug == "sakura-tokyo"
tenantSlug == "demo" && orderCount > 100
region in ["us-east", "eu-west"]

Rules are evaluated in order — the first matching rule determines the variant.

Context Variables

When evaluating a flag via OFREP, you pass a context object. Any key-value pair can be used in CEL expressions:

{
  "context": {
    "tenantSlug": "sakura-tokyo",
    "orderCount": 42,
    "region": "us-east"
  }
}

Evaluation via OFREP

Kaiten implements the OpenFeature Remote Evaluation Protocol:

POST /api/ofrep/v1/evaluate/flags/{flagKey} — single flag
POST /api/ofrep/v1/evaluate/flags — bulk evaluation

See OpenFeature (OFREP) for API details.

OpenFeature SDK Compatibility

Kaiten can be used as a flag provider with any OpenFeature SDK. Install an OFREP provider for your language and point it to your Kaiten API. See OpenFeature Providers.

See It in the Console

The Console lets you manage flags visually — create variants, configure targeting rules, and see how each flag evaluates in real time for a given instance.

Feature Flags

Create and manage flags, variants, targeting rules, and rollout strategies.

Feature Flags

Feature Flags

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