---
title: "POST /evaluate/v1/variant"
method: POST
path: "/evaluate/v1/variant"
tags: ["EvaluationService"]
---

# POST /evaluate/v1/variant

`POST /evaluate/v1/variant`

## Request body

- EvaluationRequest
  - `requestId` string
  - `namespaceKey` string, required
  - `flagKey` string, required
  - `entityId` string, required
  - `context` object, required
  - `reference` string

## Response `200`

OK

- VariantEvaluationResponse
  - `match` boolean
  - `segmentKeys` string[]
  - `reason` 'UNKNOWN_EVALUATION_REASON' | 'FLAG_DISABLED_EVALUATION_REASON' | 'MATCH_EVALUATION_REASON' | 'DEFAULT_EVALUATION_REASON', enum
  - `variantKey` string
  - `variantAttachment` string
  - `requestId` string
  - `requestDurationMillis` number, double
  - `timestamp` string, date-time
  - `flagKey` string

## Changes

> 5 revisions in range; 1 could not be searched.

- **2024-08-08** `594afc3dbe2e` — 1 breaking, 4 warning
  - the `reason` response's property type/format changed from `integer`/`enum` to `string`/`enum` for status `200`
  - added the new `DEFAULT_EVALUATION_REASON` enum value to the `reason` response property for the response status `200`
  - added the new `FLAG_DISABLED_EVALUATION_REASON` enum value to the `reason` response property for the response status `200`
  - added the new `MATCH_EVALUATION_REASON` enum value to the `reason` response property for the response status `200`
  - …1 more
- **2024-08-07** `291b2f802c58` — 1 breaking, 4 info
  - the `reason` response's property type/format changed from `string`/`enum` to `integer`/`enum` for status `200`
  - removed the `DEFAULT_EVALUATION_REASON` enum value from the `reason` response property for the response status `200`
  - removed the `FLAG_DISABLED_EVALUATION_REASON` enum value from the `reason` response property for the response status `200`
  - removed the `MATCH_EVALUATION_REASON` enum value from the `reason` response property for the response status `200`
  - …1 more

[Change history](https://skmtc.dev/flipt-io/apis/api/changes/evaluate/v1/variant/post.md)

---

[API](https://skmtc.dev/flipt-io/apis/api.md) · [All operations](https://skmtc.dev/flipt-io/apis/api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/flipt-io/api/revisions/6fe4caf26f13/schema)