## Register a requisite link

`POST /v1/requisite-links`

Creates or updates a requisite link to an owner entity. If a link for the given `(entityTypeId, entityId)` pair already exists, it is overwritten.

## Request fields (body)

| Field | Type | Required | Description |
|------|-----|:-----:|---------|
| `entityTypeId` | number | yes | Link owner type: `2` — deal, `31` — invoice. List: `GET /v1/requisite-links/fields` |
| `entityId` | number | yes | Owner entity ID. Source: `GET /v1/deals` or `GET /v1/invoices` |
| `requisiteId` | number | yes | Client requisite ID. Source: `GET /v1/requisites`. Pass `0` to skip linking |
| `bankDetailId` | number | yes | Client bank requisite ID. Source: `GET /v1/bank-details`. Pass `0` to skip linking |
| `mcRequisiteId` | number | yes | Your company's requisite ID. Source: `GET /v1/requisites`. Pass `0` to skip linking |
| `mcBankDetailId` | number | yes | Your company's bank requisite ID. Source: `GET /v1/bank-details`. Pass `0` to skip linking |

## Examples

### curl — personal key

```bash
curl -X POST "https://vibecode.bitrix24.com/v1/requisite-links" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "entityTypeId": 2,
    "entityId": 3773,
    "requisiteId": 45,
    "bankDetailId": 12,
    "mcRequisiteId": 3,
    "mcBankDetailId": 7
  }'
```

### curl — OAuth app

```bash
curl -X POST "https://vibecode.bitrix24.com/v1/requisite-links" \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "entityTypeId": 2,
    "entityId": 3773,
    "requisiteId": 45,
    "bankDetailId": 12,
    "mcRequisiteId": 3,
    "mcBankDetailId": 7
  }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/requisite-links', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    entityTypeId: 2,
    entityId: 3773,
    requisiteId: 45,
    bankDetailId: 12,
    mcRequisiteId: 3,
    mcBankDetailId: 7,
  }),
})

const { success, data } = await res.json()
console.log('Registered link for entityId:', data.entityId)
```

### JavaScript — OAuth app

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/requisite-links', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    entityTypeId: 2,
    entityId: 3773,
    requisiteId: 45,
    bankDetailId: 12,
    mcRequisiteId: 3,
    mcBankDetailId: 7,
  }),
})

const { success, data } = await res.json()
```

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data` | object | Registration result |
| `data.entityTypeId` | number | The entity type that was passed |
| `data.entityId` | number | The entity ID that was passed |
| `data.registered` | boolean | Always `true` on success |

## Response example

HTTP status: `201 Created`

```json
{
  "success": true,
  "data": {
    "entityTypeId": 2,
    "entityId": 3773,
    "registered": true
  }
}
```

## Error response example

400 — required fields missing:

```json
{
  "success": false,
  "error": {
    "code": "MISSING_FIELDS",
    "message": "POST /v1/requisite-links requires entityTypeId, entityId, requisiteId, bankDetailId, mcRequisiteId and mcBankDetailId in the body (use 0 for ids you don't want to link). Missing: requisiteId, bankDetailId, mcRequisiteId, mcBankDetailId. Raw UPPER_SNAKE names from /v1/requisite-links/fields (ENTITY_TYPE_ID, …) are accepted too."
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `MISSING_FIELDS` | One or more of the six required fields not provided |
| 422 | `BITRIX_ERROR` | Bitrix24 rejected the operation — for example, the requisite does not belong to the deal's client |
| 403 | `SCOPE_DENIED` | API key lacks the `crm` scope. Required message: `This endpoint requires 'crm' scope` |
| 401 | `TOKEN_MISSING` | API key has no configured tokens |

Full list of common API errors — [Errors](/docs/errors).

## Known specifics

**Pass `0` for unused links.** All six fields are required in the request body. If a requisite or bank requisite should not be linked, pass `0`.

**The requisite must belong to the deal's client.** To register a link for a deal, it must have a contact or company selected that owns the requisite. Without a selected client, the link returns `422 BITRIX_ERROR`.

## See also

- [Link fields](/docs/entities/requisite-links/fields)
- [Delete a link](/docs/entities/requisite-links/unregister)
- [List links](/docs/entities/requisite-links/list)
- [Requisites](/docs/entities/requisites)
- [Bank details](/docs/entities/bank-details)
- [Batch](/docs/batch)