---
title: "Attach a user to an experiment group"
method: POST
path: "/experiments/{experiment_id}/users/{user_id}"
tags: ["Experiments"]
---

# Attach a user to an experiment group

`POST /experiments/{experiment_id}/users/{user_id}`

Manually assigns a user to a specific experiment group.

## Path parameters

- `experiment_id` string, required
- `user_id` string, required

## Request body

- V4ExperimentAttachRequest
  - `group_id` string, required — ID of the experiment group to assign the user to.

## Response `204`

User attached to experiment group

## Other responses

- `400` — Invalid request
- `401` — Unauthorized
- `404` — Experiment, group, or user not found
- `409` — User already attached to experiment
- `415` — Unsupported Content-Type
- `422` — Unprocessable entity (e.g. experiment is finished)
- `429` — Too many requests
- `502` — Upstream service failure
- `504` — Upstream timeout

---

[API](https://skmtc.net/qonversion/apis/qonversion-rest-api-v4.md) · [All operations](https://skmtc.net/qonversion/apis/qonversion-rest-api-v4/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/qonversion/qonversion-rest-api-v4/versions/e3f72cf8951c/schema)