*REST API › Endpoint reference › Platform › Tags*

# Assign a tag to an entity

> Attaches an existing tag to an entity of the account.

The tag goes in the path and the entity in the body.

`POST /api/v1/tags/{tagId}/assignments` — scope `tags:write`

Scope: `tags:write` · 120/min · Idempotency-Key · MCP: `filmo_tags_assign`

## Authorizations

Bearer API key with the scope below. `tags:write`

## Headers

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `Idempotency-Key` | string | No | Unique identifier of the request, chosen by the client (a UUID works). Between 1 and 255 characters: an empty header is rejected with 400 `validation_error`, because the client would believe itself protected. Repeating the same key with the SAME body within 24 h returns the stored response without executing again, with the `Idempotent-Replay: true` header. With a DIFFERENT body it returns 422. It is the safe way to retry after a network timeout. |

## Path parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `tagId` | string | Yes | Tag identifier. |

## Body

Body schema: `TagAssignmentBody`

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `entityId` | string | Yes | Entity the tag is assigned to or removed from. |
| `entityType` | string | Yes | Type of that entity. `item`, `contact`, `order`, `space`, `project`, `kit`, `serializedItem`, `vehicle`, `staff`, `service`, `purchaseOrder`, `incident`, `repairTicket`, `opportunity`, `contract`, `invoice`, `creditNote`, `salesReceipt`, `simpleCreditNote`, `supplierInvoice` |

## Request examples

*Assign a tag to an entity*

**cURL**

```bash
curl https://app.filmo.io/api/v1/tags/tag_8f2a1c/assignments \
  --request POST \
  --header "Authorization: Bearer $FILMO_API_KEY" \
  --header "Idempotency-Key: $(uuidgen 2>/dev/null || cat /proc/sys/kernel/random/uuid)" \
  --header 'Content-Type: application/json' \
  --data '{
  "entityType": "item",
  "entityId": "itm_9f3a2b"
}'
```

**Node.js**

```javascript
fetch('https://app.filmo.io/api/v1/tags/tag_8f2a1c/assignments', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer YOUR_FILMO_API_KEY',
    'Idempotency-Key': crypto.randomUUID(),
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    entityType: 'item',
    entityId: 'itm_9f3a2b'
  })
})
```

**Python**

```python
import uuid
import requests

requests.post(
    "https://app.filmo.io/api/v1/tags/tag_8f2a1c/assignments",
    headers={
      "Authorization": "Bearer YOUR_FILMO_API_KEY",
      "Idempotency-Key": str(uuid.uuid4()),
      "Content-Type": "application/json"
    },
    json={
      "entityType": "item",
      "entityId": "itm_9f3a2b"
    }
)
```

## Response

Response schema: `TagAssignmentResultDto`

| Status | Description |
| --- | --- |
| 201 | Successful response. |
| 400 | Invalid request (validation_error): malformed query or body. `errors[]` lists every offending field with its stable code. |
| 401 | Authentication failed (unauthorized, api_key_invalid, api_key_revoked, api_key_expired, api_key_owner_inactive, api_key_owner_not_admin). |
| 403 | Not allowed (insufficient_scope: the API key does not have the required scope, named in `requiredScope`; forbidden: the owner of the key lacks the permission the operation requires). `insufficient_scope` is answered before the request counts against the rate limit, so it carries no `RateLimit-*` headers; `forbidden` does. |
| 404 | Resource not found (not_found): it does not exist or is outside the scope of the API key. |
| 409 | Conflict (conflict): the current state of the resource prevents the operation, a request with that Idempotency-Key is already in progress, or another conditional write (`If-Match`) held the resource for more than five seconds. `errors[0].code` says which: `in_progress` and `lock_timeout` are solved by retrying; `invalid_state` is not, because the state of the resource forbids the operation. |
| 422 | Idempotency-Key reused (idempotency_key_reused): the same key was used before with a different body. Change the key. |
| 429 | Rate limit exceeded (rate_limited): retry after `Retry-After` seconds; `RateLimit-*` says which quota ran out. |
| 500 | Internal error (internal_error). |

**201**

| Name | Type | Description |
| --- | --- | --- |
| `data` | object | Link between a tag and an entity. |
| `data.tagId` | string | Tag identifier. |
| `data.entityId` | string | Entity identifier. |
| `data.assigned` | boolean | true after assigning, false after removing. |
| `meta` | object | Additional information about the response. |
| `meta.warnings` | object[] | Lifecycle warnings; present only when the operation is deprecated. |
| `meta.warnings.code` | string | Stable warning code. `deprecated` |
| `meta.warnings.message` | string | For people: what is deprecated, until when, and what to use. |
| `meta.warnings.sunset` | string | Day (YYYY-MM-DD) the operation stops being served. |
| `meta.warnings.replacement` | string | `operationId` of the operation to use instead, or null if there is none. |
| `meta.warnings.link` | string | Where the deprecation is documented (the changelog). |

*Example response · 201*

```json
{
  "data": {
    "tagId": "tag_9f3a2b",
    "entityId": "entity_9f3a2b",
    "assigned": true
  }
}
```

## Errors

| Status | Codes | Meaning |
| --- | --- | --- |
| 400 | `validation_error` | Malformed query or body. `errors[]` lists every offending field with its stable code. |
| 404 | `not_found` | It does not exist or is outside the scope of the API key. |
| 409 | `conflict` | The current state of the resource prevents the operation, a request with that Idempotency-Key is already in progress, or another conditional write (`If-Match`) held the resource for more than five seconds. `errors[0].code` says which: `in_progress` and `lock_timeout` are solved by retrying; `invalid_state` is not, because the state of the resource forbids the operation. |
| 422 | `idempotency_key_reused` | The same key was used before with a different body. Change the key. |

## Deprecation

This operation is not deprecated. Deprecations are announced with a Deprecation header and a sunset date.

---

Canonical URL: https://docs.filmo.io/rest-api/endpoint-reference/tags/assign-a-tag-to-an-entity  
Last updated: 2026-10-25