# Apply a label to an email

Source: https://docs.emelia.io/docs/inbox-api/apply-label-to-email

Guide: [Inbox API](https://docs.emelia.io/docs/inbox-api.md)

`POST https://api.emelia.io/inbox/api/v1/emails/{emailId}/labels/{labelId}`

Applies a manual or AI label (ids from `GET /labels`). Idempotent: applying a label the email already has returns the same list and does not fire `label.applied` again. A real application is pushed to open inbox windows and delivered to `label.applied` webhooks. No `Idempotency-Key` handling: the operation is naturally idempotent.

## Authentication

Send your API key in the `Authorization` header: `Authorization: <your API key>`.

## Path parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `emailId` | string | yes | Inbox id of the email (from `GET /emails`, webhooks...). |
| `labelId` | string | yes | Label id, from `GET /labels`. |

## Example request

**cURL**

```bash
curl -X POST "https://api.emelia.io/inbox/api/v1/emails/cmemacme0000000000000001/labels/cmtgacme0000000000000001" \
  -H "Authorization: $EMELIA_API_KEY"
```

**JavaScript**

```js
const response = await fetch('https://api.emelia.io/inbox/api/v1/emails/cmemacme0000000000000001/labels/cmtgacme0000000000000001', {
  method: 'POST',
  headers: { Authorization: process.env.EMELIA_API_KEY },
});
console.log(await response.json());
```

**Python**

```python
import os
import requests

response = requests.post(
    "https://api.emelia.io/inbox/api/v1/emails/cmemacme0000000000000001/labels/cmtgacme0000000000000001",
    headers={"Authorization": os.environ["EMELIA_API_KEY"]},
)
print(response.json())
```

## Responses

### 200: Every label now on the email.

| Field | Type | Required | Description |
|---|---|---|---|
| `labels` | array of object | yes |  |
| `labels[].id` | string | yes |  |
| `labels[].name` | string | yes |  |
| `labels[].color` | string | yes |  |
| `labels[].isAiLabel` | boolean | yes |  |

```json
{
  "labels": [
    {
      "id": "cmtgacme0000000000000001",
      "name": "Quotes",
      "color": "#16a34a",
      "isAiLabel": false
    },
    {
      "id": "cmtgacme0000000000000002",
      "name": "Interested",
      "color": "#2563eb",
      "isAiLabel": true
    }
  ]
}
```

### 401: Missing, malformed, unknown or disabled key. No `X-RateLimit-*` headers.

| Field | Type | Required | Description |
|---|---|---|---|
| `code` | enum: `INVALID_API_KEY`, `WORKSPACE_SUSPENDED`, `FORBIDDEN`, `PLAN_REQUIRED`, `VALIDATION_FAILED`, `REQUEST_ERROR`, `PAYLOAD_TOO_LARGE`, `NOT_FOUND`, `EMAIL_NOT_FOUND`, `DRAFT_NOT_FOUND`, `MAILBOX_NOT_FOUND`, `LABEL_NOT_FOUND`, `VIEW_NOT_FOUND`, `RULE_NOT_FOUND`, `FILTER_NOT_FOUND`, `SIGNATURE_NOT_FOUND`, `MAILBOX_INACTIVE`, `INVALID_SENDER_ALIAS`, `NO_TRASH_FOLDER`, `INVALID_TAG`, `CONFLICT`, `DUPLICATE_TAG_NAME`, `DUPLICATE_RULE`, `DUPLICATE_FILTER`, `SCHEDULED_SEND_IN_PROGRESS`, `DRAFT_ALREADY_EXISTS`, `QUERY_TIMEOUT`, `RATE_LIMIT_EXCEEDED`, `QUOTA_EXCEEDED`, `INTERNAL_ERROR` | yes | Codes that the Inbox API can return, as found in the code. Branch on `code`, never on `error`. The HTTP status is derived from the code (unknown business codes are 400). |
| `error` | string | yes | Human readable. |
| `details` | object | no | Optional context: faulty fields, bounds, ids. |

```json
{
  "code": "INVALID_API_KEY",
  "error": "string",
  "details": {}
}
```

### 403: `WORKSPACE_SUSPENDED`: the Emelia subscription has expired.

| Field | Type | Required | Description |
|---|---|---|---|
| `code` | enum: `INVALID_API_KEY`, `WORKSPACE_SUSPENDED`, `FORBIDDEN`, `PLAN_REQUIRED`, `VALIDATION_FAILED`, `REQUEST_ERROR`, `PAYLOAD_TOO_LARGE`, `NOT_FOUND`, `EMAIL_NOT_FOUND`, `DRAFT_NOT_FOUND`, `MAILBOX_NOT_FOUND`, `LABEL_NOT_FOUND`, `VIEW_NOT_FOUND`, `RULE_NOT_FOUND`, `FILTER_NOT_FOUND`, `SIGNATURE_NOT_FOUND`, `MAILBOX_INACTIVE`, `INVALID_SENDER_ALIAS`, `NO_TRASH_FOLDER`, `INVALID_TAG`, `CONFLICT`, `DUPLICATE_TAG_NAME`, `DUPLICATE_RULE`, `DUPLICATE_FILTER`, `SCHEDULED_SEND_IN_PROGRESS`, `DRAFT_ALREADY_EXISTS`, `QUERY_TIMEOUT`, `RATE_LIMIT_EXCEEDED`, `QUOTA_EXCEEDED`, `INTERNAL_ERROR` | yes | Codes that the Inbox API can return, as found in the code. Branch on `code`, never on `error`. The HTTP status is derived from the code (unknown business codes are 400). |
| `error` | string | yes | Human readable. |
| `details` | object | no | Optional context: faulty fields, bounds, ids. |

```json
{
  "code": "INVALID_API_KEY",
  "error": "string",
  "details": {}
}
```

### 404: `EMAIL_NOT_FOUND` or `LABEL_NOT_FOUND`: unknown id, or it belongs to another workspace.

| Field | Type | Required | Description |
|---|---|---|---|
| `code` | enum: `INVALID_API_KEY`, `WORKSPACE_SUSPENDED`, `FORBIDDEN`, `PLAN_REQUIRED`, `VALIDATION_FAILED`, `REQUEST_ERROR`, `PAYLOAD_TOO_LARGE`, `NOT_FOUND`, `EMAIL_NOT_FOUND`, `DRAFT_NOT_FOUND`, `MAILBOX_NOT_FOUND`, `LABEL_NOT_FOUND`, `VIEW_NOT_FOUND`, `RULE_NOT_FOUND`, `FILTER_NOT_FOUND`, `SIGNATURE_NOT_FOUND`, `MAILBOX_INACTIVE`, `INVALID_SENDER_ALIAS`, `NO_TRASH_FOLDER`, `INVALID_TAG`, `CONFLICT`, `DUPLICATE_TAG_NAME`, `DUPLICATE_RULE`, `DUPLICATE_FILTER`, `SCHEDULED_SEND_IN_PROGRESS`, `DRAFT_ALREADY_EXISTS`, `QUERY_TIMEOUT`, `RATE_LIMIT_EXCEEDED`, `QUOTA_EXCEEDED`, `INTERNAL_ERROR` | yes | Codes that the Inbox API can return, as found in the code. Branch on `code`, never on `error`. The HTTP status is derived from the code (unknown business codes are 400). |
| `error` | string | yes | Human readable. |
| `details` | object | no | Optional context: faulty fields, bounds, ids. |

```json
{
  "code": "INVALID_API_KEY",
  "error": "string",
  "details": {}
}
```

### 429: `RATE_LIMIT_EXCEEDED`: per minute limit of the workspace (wait `Retry-After`). `QUOTA_EXCEEDED`: monthly quota exhausted until the 1st of next month UTC (in Emelia the plan cannot be upgraded).

| Field | Type | Required | Description |
|---|---|---|---|
| `code` | enum: `INVALID_API_KEY`, `WORKSPACE_SUSPENDED`, `FORBIDDEN`, `PLAN_REQUIRED`, `VALIDATION_FAILED`, `REQUEST_ERROR`, `PAYLOAD_TOO_LARGE`, `NOT_FOUND`, `EMAIL_NOT_FOUND`, `DRAFT_NOT_FOUND`, `MAILBOX_NOT_FOUND`, `LABEL_NOT_FOUND`, `VIEW_NOT_FOUND`, `RULE_NOT_FOUND`, `FILTER_NOT_FOUND`, `SIGNATURE_NOT_FOUND`, `MAILBOX_INACTIVE`, `INVALID_SENDER_ALIAS`, `NO_TRASH_FOLDER`, `INVALID_TAG`, `CONFLICT`, `DUPLICATE_TAG_NAME`, `DUPLICATE_RULE`, `DUPLICATE_FILTER`, `SCHEDULED_SEND_IN_PROGRESS`, `DRAFT_ALREADY_EXISTS`, `QUERY_TIMEOUT`, `RATE_LIMIT_EXCEEDED`, `QUOTA_EXCEEDED`, `INTERNAL_ERROR` | yes | Codes that the Inbox API can return, as found in the code. Branch on `code`, never on `error`. The HTTP status is derived from the code (unknown business codes are 400). |
| `error` | string | yes | Human readable. |
| `details` | object | no | Optional context: faulty fields, bounds, ids. |

```json
{
  "code": "INVALID_API_KEY",
  "error": "string",
  "details": {}
}
```

### 500: `INTERNAL_ERROR`: unexpected failure. The message is generic in production.

| Field | Type | Required | Description |
|---|---|---|---|
| `code` | enum: `INVALID_API_KEY`, `WORKSPACE_SUSPENDED`, `FORBIDDEN`, `PLAN_REQUIRED`, `VALIDATION_FAILED`, `REQUEST_ERROR`, `PAYLOAD_TOO_LARGE`, `NOT_FOUND`, `EMAIL_NOT_FOUND`, `DRAFT_NOT_FOUND`, `MAILBOX_NOT_FOUND`, `LABEL_NOT_FOUND`, `VIEW_NOT_FOUND`, `RULE_NOT_FOUND`, `FILTER_NOT_FOUND`, `SIGNATURE_NOT_FOUND`, `MAILBOX_INACTIVE`, `INVALID_SENDER_ALIAS`, `NO_TRASH_FOLDER`, `INVALID_TAG`, `CONFLICT`, `DUPLICATE_TAG_NAME`, `DUPLICATE_RULE`, `DUPLICATE_FILTER`, `SCHEDULED_SEND_IN_PROGRESS`, `DRAFT_ALREADY_EXISTS`, `QUERY_TIMEOUT`, `RATE_LIMIT_EXCEEDED`, `QUOTA_EXCEEDED`, `INTERNAL_ERROR` | yes | Codes that the Inbox API can return, as found in the code. Branch on `code`, never on `error`. The HTTP status is derived from the code (unknown business codes are 400). |
| `error` | string | yes | Human readable. |
| `details` | object | no | Optional context: faulty fields, bounds, ids. |

```json
{
  "code": "INVALID_API_KEY",
  "error": "string",
  "details": {}
}
```