# Create an inbox filter

Source: https://docs.emelia.io/docs/inbox-api/create-inbox-filter

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

`POST https://api.emelia.io/inbox/api/v1/filters`

Evaluated when listing, so it also hides past emails, and deleting it brings them back. Addresses and domains are stored lowercase; a leading `@` on a domain is dropped. A `label` filter must reference a label of the workspace. Supports `Idempotency-Key`.

## Authentication

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

## Request body

Content type: `application/json`, required.

`sender`: an email address, exact match, case insensitive. `domain`: a domain such as example.com (leading @ dropped). `subject`: text contained in the subject. `label`: id of a manual or AI label of the workspace.

| Field | Type | Required | Description |
|---|---|---|---|
| `type` | enum: `sender`, `domain`, `subject`, `label` | yes |  |
| `value` | string | yes | Min length 1. |

```json
{
  "type": "domain",
  "value": "newsletter.example.com"
}
```

## Example request

**cURL**

```bash
curl -X POST "https://api.emelia.io/inbox/api/v1/filters" \
  -H "Authorization: $EMELIA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "type": "domain",
  "value": "newsletter.example.com"
}'
```

**JavaScript**

```js
const response = await fetch('https://api.emelia.io/inbox/api/v1/filters', {
  method: 'POST',
  headers: { Authorization: process.env.EMELIA_API_KEY, 'Content-Type': 'application/json' },
  body: JSON.stringify({
    "type": "domain",
    "value": "newsletter.example.com"
  }),
});
console.log(await response.json());
```

**Python**

```python
import os
import requests

response = requests.post(
    "https://api.emelia.io/inbox/api/v1/filters",
    headers={"Authorization": os.environ["EMELIA_API_KEY"]},
    json={
        "type": "domain",
        "value": "newsletter.example.com"
    },
)
print(response.json())
```

## Responses

### 201: Created.

| Field | Type | Required | Description |
|---|---|---|---|
| `filter` | object | yes |  |
| `filter.id` | string | yes |  |
| `filter.type` | enum: `sender`, `domain`, `subject`, `label` | yes |  |
| `filter.value` | string | yes |  |
| `filter.label` | object or null | yes | The targeted label when `type` is `label`. |
| `filter.createdAt` | string (date-time) | yes |  |
| `filter.updatedAt` | string (date-time) | yes |  |

```json
{
  "filter": {
    "id": "cmflacme0000000000000001",
    "type": "domain",
    "value": "newsletter.example.com",
    "label": null,
    "createdAt": "2026-10-01T12:00:00.000Z",
    "updatedAt": "2026-10-01T12:00:00.000Z"
  }
}
```

### 400: `VALIDATION_FAILED`: unknown `type`, or a `value` that is not an address, a domain or an id.

| 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": {}
}
```

### 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: `LABEL_NOT_FOUND`: the label of a `label` filter does not exist, or belongs to another workspace (never 403, to prevent enumeration).

| 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": {}
}
```

### 409: `DUPLICATE_FILTER` (`details.filterId` names the existing one) or `CONFLICT` (idempotency).

| 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": {}
}
```

### 413: `PAYLOAD_TOO_LARGE`: JSON body above 256 KB.

| 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": {}
}
```