> For the complete documentation index, see [llms.txt](https://www.docpartner.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.docpartner.dev/en/api/sms-partner/send-sms/character-counter.md).

# Character counter

Estimate an SMS before sending: number of segments, detected encoding, unit price and total cost, based on your account's rate.

## URL

`POST` `https://api.smspartner.fr/v1/sms/estimate`

Rate limit: 30 requests / 30 seconds

## Parameters

<table><thead><tr><th width="220">Name</th><th>Value</th></tr></thead><tbody><tr><td><code>apiKey</code></td><td><a href="https://my.smspartner.fr/dashboard/api/paramaters">Your API key</a></td></tr><tr><td><code>text</code></td><td><strong>Required.</strong> Content of the message to estimate. 10,000 characters maximum.</td></tr><tr><td><code>country</code></td><td>Optional. ISO 3166-1 alpha-2 country code (e.g. <code>FR</code>, <code>BE</code>) used to determine the rate. Default value: <code>FR</code>.</td></tr></tbody></table>

{% hint style="info" %}
A message cannot exceed **10 SMS** (segments). Beyond that, the API returns an error.
{% endhint %}

## Example request

```json
{
    "apiKey": "xxx",
    "text": "Thanks for your order, delivery expected tomorrow before noon!",
    "country": "FR"
}
```

## Response

<table><thead><tr><th width="220">Field</th><th>Value</th></tr></thead><tbody><tr><td><code>sms_count</code></td><td>Number of SMS segments needed to send the message.</td></tr><tr><td><code>encoding</code></td><td>Detected encoding: <code>GSM-7</code> (standard alphabet) or <code>UCS-2</code> (Unicode characters, e.g. emojis, extended accents).</td></tr><tr><td><code>cost_per_sms</code></td><td>Unit price per SMS segment, based on your account's rate.</td></tr><tr><td><code>total_cost</code></td><td>Estimated total cost (<code>cost_per_sms</code> × <code>sms_count</code>).</td></tr><tr><td><code>is_unicode_required</code></td><td>Present and set to <code>true</code> only when the encoding is <code>UCS-2</code> (the message contains Unicode characters). Absent otherwise.</td></tr></tbody></table>

{% tabs %}
{% tab title="Response (UCS-2)" %}

```json
{
    "sms_count": 2,
    "encoding": "UCS-2",
    "cost_per_sms": 0.038,
    "total_cost": 0.076,
    "is_unicode_required": true
}
```

{% endtab %}

{% tab title="Response (GSM-7)" %}

```json
{
    "sms_count": 1,
    "encoding": "GSM-7",
    "cost_per_sms": 0.038,
    "total_cost": 0.038
}
```

{% endtab %}
{% endtabs %}

## Errors

On error, the response has the form `{ "success": false, "message": "..." }` with the corresponding HTTP status.

<table><thead><tr><th width="160">HTTP status</th><th>Case</th></tr></thead><tbody><tr><td><code>400</code></td><td>Invalid JSON, missing <code>text</code> parameter, <code>text</code> longer than 10,000 characters, or message exceeding 10 SMS.</td></tr><tr><td><code>401</code></td><td><code>apiKey</code> missing or invalid.</td></tr><tr><td><code>429</code></td><td>Rate limit exceeded (30 requests / 30 seconds).</td></tr></tbody></table>


---

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