## POST /api/v2/domains/{id}/dyndns

**Create a DynDNS configuration**

Create a dynamic DNS updater token for a hostname under the domain. The hostname must be the domain itself or a subdomain of it, and recordType must be A or AAAA. Store the returned token securely because it authorizes public DynDNS updates for this hostname.

### Related Endpoints

- `GET /api/v2/domains/{id}/dyndns`: List DynDNS configurations
- `PATCH /api/v2/domains/{id}/dyndns/{configId}`: Enable or disable DynDNS
- `DELETE /api/v2/domains/{id}/dyndns/{configId}`: Delete a DynDNS configuration

### Headers

- `Accept`: application/json
- `Authorization`: Bearer YOUR_API_KEY
- Required API scope: `write:domains`
- `Content-Type`: application/json

### Parameters

- `id` (path, string, required): Public domain ID. Get it from GET /api/v2/domains `data[].id`. Do not invent this value; use the exact ID returned by the referenced API response. Example: `dom_01hxa3b4c5d6e7f8g9h0j1k2m3`

### Request Body

- `hostname` (string, required) Example: `home.example.com`
- `recordType` (string, required) Example: `A`
  Allowed values: A, AAAA

### Request Examples

#### Create IPv4 DynDNS

```bash
curl -X POST "https://cloud.hostup.se/api/v2/domains/dom_01hxa3b4c5d6e7f8g9h0j1k2m3/dyndns" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json" \
  -H "Content-Type: application/json" \
  -d '{
    "hostname": "home.example.com",
    "recordType": "A"
  }'
```

```json
{
  "hostname": "home.example.com",
  "recordType": "A"
}
```

#### Create IPv6 DynDNS

```bash
curl -X POST "https://cloud.hostup.se/api/v2/domains/dom_01hxa3b4c5d6e7f8g9h0j1k2m3/dyndns" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json" \
  -H "Content-Type: application/json" \
  -d '{
    "hostname": "ipv6.example.com",
    "recordType": "AAAA"
  }'
```

```json
{
  "hostname": "ipv6.example.com",
  "recordType": "AAAA"
}
```

### Response Schema

- `id` (string, required) Example: `ddns_01hxa3b4c5d6e7f8g9h0j1k2m3`
- `hostname` (string, required) Example: `home.example.com`
- `recordType` (string, required) Example: `A`
  Allowed values: A, AAAA
- `token` (string | null, required) Example: `0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef`
- `lastIp` (string | null, required) Example: `203.0.113.45`
- `lastUpdatedAt` (string | null, required) Example: `2026-04-27T12:00:00.000Z`
- `updateCount` (integer, required) Example: `12`
- `enabled` (boolean, required) Example: `true`
- `createdAt` (string | null, required) Example: `2026-04-20T08:00:00.000Z`
- `updatedAt` (string | null, required) Example: `2026-04-27T12:00:00.000Z`

### Responses

#### 201 - Created DynDNS configuration. The token is visible because write access is required.
```json
{
  "id": "ddns_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "hostname": "home.example.com",
  "recordType": "A",
  "token": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
  "lastIp": null,
  "lastUpdatedAt": null,
  "updateCount": 0,
  "enabled": true,
  "createdAt": "2026-04-27T12:00:00.000Z",
  "updatedAt": null
}
```

#### 400 - Invalid request. The response body is an RFC 7807 Problem Details document.
```json
{
  "type": "https://developer.hostup.se/errors/invalid_request",
  "title": "Invalid request",
  "status": 400,
  "detail": "The request body failed validation.",
  "code": "invalid_request",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z",
  "errors": [
    {
      "pointer": "/items/0/domainName",
      "detail": "`domainName` is required.",
      "code": "invalid_request"
    }
  ]
}
```

#### 401 - Unauthorized. Authentication is required.
```json
{
  "type": "https://developer.hostup.se/errors/unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Authentication is required.",
  "code": "unauthorized",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 403 - Forbidden. The caller lacks a required scope or does not own the resource.
```json
{
  "type": "https://developer.hostup.se/errors/forbidden",
  "title": "Forbidden",
  "status": 403,
  "detail": "The caller lacks a required scope or does not own the resource.",
  "code": "forbidden",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 404 - Not found. The resource does not exist or is not owned by the caller.
```json
{
  "type": "https://developer.hostup.se/errors/not_found",
  "title": "Not found",
  "status": 404,
  "detail": "The requested resource could not be found.",
  "code": "not_found",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 429 - Rate limited. Retry after the limit resets. 429 responses include `Retry-After` seconds plus `X-RateLimit-*` headers.
```json
{
  "type": "https://developer.hostup.se/errors/rate_limit_exceeded",
  "title": "Too many requests",
  "status": 429,
  "detail": "Too many requests. Retry after the limit resets.",
  "code": "rate_limit_exceeded",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 500 - Internal error. Retry later or contact support if the issue persists.
```json
{
  "type": "https://developer.hostup.se/errors/internal_error",
  "title": "Internal server error",
  "status": 500,
  "detail": "An unexpected error occurred. Retry later or contact support if the issue persists.",
  "code": "internal_error",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```