# Create a segment

Source: https://joinsimplesms.com/docs/api/segments/create
Index: https://joinsimplesms.com/llms.txt

`POST /v1/segments`

A segment is a saved, named filter over contacts (an audience; not an SMS message part). It is evaluated when used, so it always reflects current contacts. Up to 100 segments, 10 rules each.

Send your API key as a bearer token: `Authorization: Bearer ssms_sk_...`. Test keys run this endpoint against the [sandbox](/docs/sandbox); see [Authentication](/docs/authentication) for key modes and scopes.

## Request body

JSON (`Content-Type: application/json`).

A `SegmentInput` object.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `name` | string | No | At most 80 characters. |
| `description` | string | No | At most 200 characters. Nullable. |
| `match` | `all`, `any` | No | Default "all". |
| `rules` | array of SegmentRule | No | At most 10 items. |

## Responses

| Status | Meaning | Body |
| --- | --- | --- |
| 201 | The segment | `Segment` |
| 400 | Invalid rules, or the segment limit is reached | `Error` |
| 401 | Missing, malformed, or revoked API key | `Error` |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged | `Error` |
| 429 | Rate limit or quota exceeded | `Error` |

### 201: `Segment` fields

| Field | Type | Description |
| --- | --- | --- |
| `id` | string | Example: `seg_a1B2c3D4e5F6`. |
| `object` | `segment` |  |
| `name` | string |  |
| `description` | string | Nullable. |
| `match` | `all`, `any` |  |
| `rules` | array of SegmentRule |  |
| `created_at` | string (date-time) |  |
| `updated_at` | string (date-time) |  |

## Errors

| Status | When |
| --- | --- |
| 400 | Invalid rules, or the segment limit is reached |
| 401 | Missing, malformed, or revoked API key |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged |
| 429 | Rate limit or quota exceeded |

Every error has the same JSON shape, and `request_id` matches the `X-Request-Id` response header. [Errors](/docs/errors) lists every code and what to do about it.

```json
{
  "error": {
    "code": "invalid_request",
    "message": "What went wrong, in plain words.",
    "param": "the_field",
    "request_id": "req_a1B2c3D4e5F6g7H8"
  }
}
```

## Examples

### curl

```bash
curl -X POST "https://api.joinsimplesms.com/v1/segments" \
  -H "Authorization: Bearer $SIMPLESMS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "rules": [
    {
      "field": "tag",
      "op": "is",
      "value": "vip"
    },
    {
      "field": "state",
      "op": "is",
      "value": "TN"
    },
    {
      "field": "field",
      "key": "plan",
      "op": "is",
      "value": "pro"
    },
    {
      "field": "topic",
      "key": "tp_marketing",
      "op": "is",
      "value": "subscribed"
    }
  ]
}'
```

### Node.js

The Node.js SDK does not wrap this endpoint yet; call it with `fetch`.

```javascript
const res = await fetch('https://api.joinsimplesms.com/v1/segments', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.SIMPLESMS_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "rules": [
      {
        "field": "tag",
        "op": "is",
        "value": "vip"
      },
      {
        "field": "state",
        "op": "is",
        "value": "TN"
      },
      {
        "field": "field",
        "key": "plan",
        "op": "is",
        "value": "pro"
      },
      {
        "field": "topic",
        "key": "tp_marketing",
        "op": "is",
        "value": "subscribed"
      }
    ]
  }),
});

if (!res.ok) throw new Error((await res.json()).error.message);
const data = await res.json();
```

### Python

The Python SDK does not wrap this endpoint yet; call it over HTTP.

```python
import json, os, urllib.request

req = urllib.request.Request(
    "https://api.joinsimplesms.com/v1/segments",
    method="POST",
    headers={
        "Authorization": f"Bearer {os.environ['SIMPLESMS_API_KEY']}",
        "Content-Type": "application/json",
    },
    data=json.dumps({
        "rules": [
            {
                "field": "tag",
                "op": "is",
                "value": "vip"
            },
            {
                "field": "state",
                "op": "is",
                "value": "TN"
            },
            {
                "field": "field",
                "key": "plan",
                "op": "is",
                "value": "pro"
            },
            {
                "field": "topic",
                "key": "tp_marketing",
                "op": "is",
                "value": "subscribed"
            }
        ]
    }).encode(),
)
with urllib.request.urlopen(req) as res:
    data = json.load(res)
```

## Related

- Guide: [Contacts](/docs/contacts)
- [All segments endpoints](/docs/api#segments)
- [API reference](/docs/api)