> ## Documentation Index
> Fetch the complete documentation index at: https://developers.senderz.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Register a Sender ID

> Submit a new Sender ID for registration on a market register.

**Required permission:** `sids:write`

The owning brand must be in `verified` status before a SID can be registered.

## Request body

<ParamField body="sender_id" type="string" required>
  The alphanumeric Sender ID. 2-11 characters. Cannot be numbers only.
</ParamField>

<ParamField body="brand_id" type="string" required>
  Reference to a previously onboarded and verified brand entity.
</ParamField>

<ParamField body="market" type="string" required>
  ISO 3166-1 alpha-2 country code. Determines which register and validation rules apply.
</ParamField>

<ParamField body="use_case" type="string" required>
  Plain-text description of intended message content.
</ParamField>

<ParamField body="match_type" type="string" required>
  One of: `business_name`, `company_name`, `trademark`, `domain`.
</ParamField>

<ParamField body="match_value" type="string" required>
  The registered name, mark, or domain the SID matches against.
</ParamField>

## Example

```bash theme={null}
curl -X POST https://api.senderz.ai/v1/sids \
  -H "Authorization: Bearer sz_live_xxxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "sender_id": "TrackFast",
    "brand_id": "brand_f6g7h8i9",
    "market": "AU",
    "use_case": "Dispatch and delivery notifications for e-commerce orders.",
    "match_type": "business_name",
    "match_value": "TrackFast Logistics Pty Ltd"
  }'
```

## Response

<ResponseExample>
  ```json 201 theme={null}
  {
    "ok": true,
    "data": {
      "id": "sid_j1k2l3m4",
      "sender_id": "TrackFast",
      "brand_id": "brand_f6g7h8i9",
      "market": "AU",
      "status": "pending_review",
      "match_type": "business_name",
      "match_value": "TrackFast Logistics Pty Ltd",
      "created_at": "2026-07-17T14:30:00+10:00"
    },
    "meta": {
      "request_id": "req_yza567",
      "timestamp": "2026-07-17T14:30:00+10:00"
    }
  }
  ```
</ResponseExample>