---
title: "Read one arm of an experiment"
method: GET
path: "/v1/experiments/{experiment_id}/arms/{arm_id}"
tags: ["experiments"]
---

# Read one arm of an experiment

`GET /v1/experiments/{experiment_id}/arms/{arm_id}`

## Request

- Base URL: `https://api.octaneai.com`
- URL: `https://api.octaneai.com/v1/experiments/{experiment_id}/arms/{arm_id}`
- Auth: HTTP bearer

## Path parameters

- `experiment_id` string, required
- `arm_id` string, required

## Response `200`

One arm of the experiment: the version it renders and its share of the split.

- ExperimentArmDetail: One arm on its own: the arm as the experiment lists it, plus the experiment it belongs to.
  - `id` string, required
  - `position` integer, required: 0 for the live version, 1 for the variant
  - `label` string, required
  - `weight` integer, required: The arm's share of the split, a whole number weighed against the other arm's
  - `version_id` string, required
  - `version_number` integer, required
  - `is_control` boolean, required
  - `experiment_id` string, required

## Other responses

- `401`: The key is missing, malformed, revoked or expired.
- `403`: The store's plan has no API access, or the key lacks the scope.
- `404`: Not found
- `422`: A request parameter is invalid.
- `429`: The key's or the store's bucket is full; Retry-After says when to try again.
- `504`: The request timed out.

---

[API](https://skmtc.dev/octaneai/apis/octane-ai-merchant-api.md) - [All operations](https://skmtc.dev/octaneai/apis/octane-ai-merchant-api/llms.txt) - [OpenAPI document](https://skmtc.dev/octaneai/apis/octane-ai-merchant-api/revisions/dc2d1aa2b7c6?raw)