# Add a Member to a Group

One of your tenant's users joins the group.

## Overview

- `userId`: a user of your tenant whose account is not deleted — `404` `GROUP_USER_NOT_FOUND` (`No such user in the tenant`) otherwise. Any role may be a member: a group grants no permission.
- `200` with the group, its `memberCount` counting the new member. Already in it: `409` `GROUP_ALREADY_MEMBER`.
- A policy decision reads the membership as it is then: the new member counts for every operation decided from now on ([Policy Sets & Groups](https://docs.aureahub.com/docs/guide-policy-sets.md)).
- For `owner`, `tenantadmin`, `non_signing_admin` and `security_admin`.

## Endpoint

### `POST /v1/groups/{groupId}/members`

Authentication: bearer token required.

Adds one of your tenant's users to a group.

**Path parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `groupId` | string (uuid) | yes | The group's id |

**Request body**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `userId` | string (uuid) | yes | A user of your tenant |

**Responses**

`200` Added

```json
{
  "id": "3b8e1f6a-2c4d-4e9f-a1b7-6d5c4e3f2a10",
  "name": "Finance approvers",
  "description": "Approve transfers above 10,000 EUR",
  "memberCount": 3,
  "createdBy": "5d2c1b0a-9e8f-4a7b-8c6d-5e4f3a2b1c0d",
  "createdAt": "2026-10-08T09:12:40.118Z",
  "updatedAt": "2026-10-08T09:20:03.552Z"
}
```

`409` Member already

```json
{
  "statusCode": 409,
  "error": "ConflictError",
  "message": "The user is a member already",
  "details": { "code": "GROUP_ALREADY_MEMBER" }
}
```

`404` No such user

```json
{
  "statusCode": 404,
  "error": "NotFoundError",
  "message": "No such user in the tenant",
  "details": { "code": "GROUP_USER_NOT_FOUND" }
}
```

**Example request**

```bash
curl -X POST https://api.aureahub.com/v1/groups/$GROUP_ID/members \
  -H "Authorization: Bearer $ADMIN_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "userId": "0d2f6b8a-4c1e-4a93-b7d5-2e9f1c3a8b60" }'
```

---

Web version: https://docs.aureahub.com/#group-member-add