# Make a verified email address the user's primary address

`POST /v1/users/{user_id}/emails/{email_id}:set-primary` · permission `users:write`

Makes a verified address the user's primary address; the previous primary stays as a secondary address. An unverified address cannot become primary. If the address is already primary nothing is written and `200` is returned. The change is written to the management audit log as `user.primary_email_changed` with the API key as actor, and emits `user.updated`.

## Request

| Parameter | In | Required | Description |
|---|---|---|---|
| `user_id` | path | yes | User id, prefixed `usr_`. |
| `email_id` | path | yes | Id of the email row (internal UUID, lowercase, hyphenated), as returned by `GET /v1/users/{user_id}/emails`. |

The request takes no body (an empty body or `{}` is accepted).

## Response

`200 OK` with the updated email row. Without the `users:read_pii` permission the address is masked (`a***@e***.com`).

```json
{
  "id": "0191f0a0-3333-7444-8555-666666666666",
  "email": "ada@example.com",
  "verified": true,
  "primary": true,
  "created_at": "2026-01-15T09:30:00Z"
}
```

## Errors

Every error is an `application/problem+json` body with a stable `code`.

| HTTP | `code` | When |
|---|---|---|
| 400 | `malformed_request`, `unknown_field` | The body is not valid JSON, or is neither empty nor `{}`. |
| 409 | `primary_requires_verified` | The address is not verified. |
| 404 | `not_found` | The user or the email row does not exist in this environment, the email does not belong to this user, or an id is malformed. |
| 401 | `unauthenticated` | The API key is missing, invalid or revoked. |
| 403 | `insufficient_permissions` | The key lacks the `users:write` permission. |
| 429 | `rate_limited` | The rate limit was exceeded; honor `Retry-After`. |
| 503 | `service_unavailable` | A dependency is temporarily unavailable; retry later. |

## Example

```bash
curl -X POST https://api.eu.keenauth.com/v1/users/usr_0a1b2c3d4e5f6g7h8j9k0m1n2p/emails/0191f0a0-3333-7444-8555-666666666666:set-primary \
  -H "Authorization: Bearer $KEENAUTH_SECRET_KEY"
```

## Personal data

This endpoint carries personal data: end-user profile. [Personal data in the KeenAuth APIs](/docs/policies/personal-data) describes what is stored, how long it is kept and how it is deleted. Do not send special categories of personal data (health, biometric data, religion, political opinions, sexual orientation) in any field.