---
title: "Create or update evaluation for an experiment run"
method: POST
path: "/v1/experiment_evaluations"
tags: ["experiments"]
---

# Create or update evaluation for an experiment run

`POST /v1/experiment_evaluations`

## Request body

- UpsertExperimentEvaluationRequestBody
  - `experiment_run_id` string, required — The ID of the experiment run being evaluated
  - `name` string, required — The name of the evaluation
  - `annotator_kind` 'LLM' | 'CODE' | 'HUMAN', required — The kind of annotator used for the evaluation
  - `start_time` string, date-time, required — The start time of the evaluation in ISO format
  - `end_time` string, date-time, required — The end time of the evaluation in ISO format
  - `result` ExperimentEvaluationResult
    - `label` string, nullable — The label assigned by the evaluation
    - `score` number, nullable — The score assigned by the evaluation
    - `explanation` string, nullable — Explanation of the evaluation result
  - `error` string, nullable — Error message if the evaluation encountered an error. Either result or error must be provided.
  - `metadata` object, nullable — Metadata for the evaluation
  - `trace_id` string, nullable — Optional trace ID for tracking

## Response `200`

Successful Response

- UpsertExperimentEvaluationResponseBody
  - `data` UpsertExperimentEvaluationResponseBodyData, required
    - `id` string, required — The ID of the upserted experiment evaluation

## Other responses

- `403` — Forbidden
- `404` — Experiment run not found
- `422` — Validation Error

---

[API](https://skmtc.net/arize-ai/apis/arize-phoenix-rest-api.md) · [All operations](https://skmtc.net/arize-ai/apis/arize-phoenix-rest-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/arize-ai/arize-phoenix-rest-api/versions/a14d8ad6f708/schema)