Evaluate Flag

curl -X POST https://fly.feather.mupeni.dev/v1/evaluate \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "flagKey": "new-checkout",
    "context": {
      "userId": "user_123",
      "attributes": { "country": "DE", "plan": "pro" }
    }
  }'

{
  "flagKey": "new-checkout",
  "value": true,
  "reason": "RULE_MATCH",
  "ruleId": "rule_beta",
  "requestId": "9fd3e4bc-5f2a-4ba2-b7f4-8a74054b8132"
}

{
  "flagKey": "new-checkout",
  "value": null,
  "reason": "ERROR"
}

POST

evaluate

curl -X POST https://fly.feather.mupeni.dev/v1/evaluate \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "flagKey": "new-checkout",
    "context": {
      "userId": "user_123",
      "attributes": { "country": "DE", "plan": "pro" }
    }
  }'

{
  "flagKey": "new-checkout",
  "value": true,
  "reason": "RULE_MATCH",
  "ruleId": "rule_beta",
  "requestId": "9fd3e4bc-5f2a-4ba2-b7f4-8a74054b8132"
}

{
  "flagKey": "new-checkout",
  "value": null,
  "reason": "ERROR"
}

Returns the resolved flag value and evaluation reason from the edge bundle cache. Auth: API key only (Authorization: Bearer <key>).

Body

string

required

The flag key to evaluate.

object

required

Evaluation context.

string

Stable user identifier.

string

Anonymous identifier when userId is not available.

Record<string, string | number | boolean>

Additional attributes used by flag rules.

Response

string

required

boolean | string | number | null

required

required

string

required

Client keys (pk_...) cannot evaluate non-clientSafe flags. Those evaluations are masked as FLAG_NOT_FOUND.

Status codes

Status	Meaning
`200`	Evaluation succeeded
`400`	Invalid JSON body (`INVALID_JSON`)
`401`	Missing/invalid API key (`UNAUTHORIZED`, `INVALID_API_KEY`)
`422`	Validation failed (`VALIDATION_ERROR`)
`429`	Rate-limited (`RATE_LIMITED`)
`503`	Bundle unavailable; returns `reason: "ERROR"`

curl -X POST https://fly.feather.mupeni.dev/v1/evaluate \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "flagKey": "new-checkout",
    "context": {
      "userId": "user_123",
      "attributes": { "country": "DE", "plan": "pro" }
    }
  }'

{
  "flagKey": "new-checkout",
  "value": true,
  "reason": "RULE_MATCH",
  "ruleId": "rule_beta",
  "requestId": "9fd3e4bc-5f2a-4ba2-b7f4-8a74054b8132"
}

{
  "flagKey": "new-checkout",
  "value": null,
  "reason": "ERROR"
}

Delivery API Overview Evaluate Flags (Bulk)

Getting Started

Concepts

Management API

Delivery API

Body

Response

Status codes

​Body

​Response

​Status codes

Body

Response

Status codes