> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.pinnacle.sh/v-2/api-reference/messages/validate-sms/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.pinnacle.sh/_mcp/server.

# Validate SMS Message

POST https://api.pinnacle.sh/messages/validate/sms
Content-Type: application/json

Validate SMS message content without sending it.

Reference: https://docs.pinnacle.sh/api-reference/messages/validate-sms

## Authentication

- `PINNACLE-API-KEY` header (required) — API Key authentication via header

## Request

### Body (application/json)

This endpoint expects a SMSContent.

- `text` (string, required) — Message content.

## Response

### 200

Returns the validation results.

- `segments` (SmsValidationResponseSegments, required) — Details about how the SMS content would be segmented for delivery.
- `total` (SmsValidationResponseTotal, required)
- `unit` (double, required) — Cost per message segment.
- `isOverSegmentLimit` (boolean, optional) — Indicates if the message exceeds the allowed segment limit.  For SMS, this is limit is 10.

## Errors

### 400 Bad Request Error

Validation failed. The payload has missing required fields and/or invalid types.  See [https://zod.dev/error-formatting](https://zod.dev/error-formatting) for more information.

- `description` (string, required) — Human-readable summary of validation failures.
- `errors` (ZodErrorErrors, required) — Structured dictionary of issues containing two main sections: - `errors`: Array of global validation errors not tied to specific fields - `properties`: Object mapping field names to their specific validation errors, where each field contains an `errors` array

### 401 Unauthorized Error

The request lacks valid authentication credentials or the provided credentials are invalid.  Ensure you're including a valid API key in the request headers and that your account has the necessary permissions to access this endpoint.

- `error` (string, required) — Human-readable description of the error that occurred, corresponding to the HTTP status code.

### 403 Forbidden Error

Your subscription does not include access to this feature.  This occurs when attempting to use functionality that requires a higher subscription tier. Please upgrade your subscription to access this feature.

- `error` (string, required) — Human-readable description of the error that occurred, corresponding to the HTTP status code.

### 500 Internal Server Error

An unexpected error occurred on Pinnacle's servers while processing your request.  If this error persists, please contact support with the request details.

- `error` (string, required) — Human-readable description of the error that occurred, corresponding to the HTTP status code.

## Types

### SmsValidationResponseSegments

Details about how the SMS content would be segmented for delivery.

- `gsm7` (SmsValidationResponseSegmentsGsm7, required) — Segmentation details when your message is encoded with GSM-7.
- `utf16` (SmsValidationResponseSegmentsUtf16, required) — Segmentation details when your message is encoded with UTF-16.

### SmsValidationResponseTotal

- `gsm7` (double, required) — Total price of this message. Calculated by multiplying the number of GSM-7 segments by the unit cost.  You must remove all unsupported UTF-16 characters before this message can be sent as GSM-7.
- `utf16` (double, required) — Total price of this message. Calculated by multiplying the number of UTF-16 segments by the unit cost.

### ZodErrorErrors

Structured dictionary of issues containing two main sections: - `errors`: Array of global validation errors not tied to specific fields - `properties`: Object mapping field names to their specific validation errors, where each field contains an `errors` array

### SmsValidationResponseSegmentsGsm7

Segmentation details when your message is encoded with GSM-7.

- `totalBytes` (integer, required) — Total number of bytes used by the GSM-7 segments.
- `unsupported` (list of string, required) — Characters not supported by GSM-7 encoding.
- `value` (list of string, required) — Message broken down into segments using GSM-7 encoding.

### SmsValidationResponseSegmentsUtf16

Segmentation details when your message is encoded with UTF-16.

- `totalBytes` (integer, required) — Total number of bytes used by the UTF-16 segments.
- `value` (list of string, required) — Message broken down into segments using UTF-16 encoding.

## Examples

**Request**

```json
{
  "text": "Hello from Pinnacle"
}
```

**Response**

```json
{
  "segments": {
    "gsm7": {
      "totalBytes": 11,
      "unsupported": [],
      "value": [
        "Hello from Pinnacle"
      ]
    },
    "utf16": {
      "totalBytes": 24,
      "value": [
        "Hello from Pinnacle"
      ]
    }
  },
  "total": {
    "gsm7": 0.01,
    "utf16": 0.01
  },
  "unit": 0.01,
  "isOverSegmentLimit": false
}
```

**SDK Code**

```python SMS Validation
import requests

url = "https://api.pinnacle.sh/messages/validate/sms"

payload = { "text": "Hello from Pinnacle" }
headers = {
    "PINNACLE-API-KEY": "<apiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript SMS Validation
const url = 'https://api.pinnacle.sh/messages/validate/sms';
const options = {
  method: 'POST',
  headers: {'PINNACLE-API-KEY': '<apiKey>', 'Content-Type': 'application/json'},
  body: '{"text":"Hello from Pinnacle"}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go SMS Validation
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.pinnacle.sh/messages/validate/sms"

	payload := strings.NewReader("{\n  \"text\": \"Hello from Pinnacle\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("PINNACLE-API-KEY", "<apiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby SMS Validation
require 'uri'
require 'net/http'

url = URI("https://api.pinnacle.sh/messages/validate/sms")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["PINNACLE-API-KEY"] = '<apiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"text\": \"Hello from Pinnacle\"\n}"

response = http.request(request)
puts response.read_body
```

```java SMS Validation
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.pinnacle.sh/messages/validate/sms")
  .header("PINNACLE-API-KEY", "<apiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"text\": \"Hello from Pinnacle\"\n}")
  .asString();
```

```php SMS Validation
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.pinnacle.sh/messages/validate/sms', [
  'body' => '{
  "text": "Hello from Pinnacle"
}',
  'headers' => [
    'Content-Type' => 'application/json',
    'PINNACLE-API-KEY' => '<apiKey>',
  ],
]);

echo $response->getBody();
```

```csharp SMS Validation
using RestSharp;

var client = new RestClient("https://api.pinnacle.sh/messages/validate/sms");
var request = new RestRequest(Method.POST);
request.AddHeader("PINNACLE-API-KEY", "<apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"text\": \"Hello from Pinnacle\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift SMS Validation
import Foundation

let headers = [
  "PINNACLE-API-KEY": "<apiKey>",
  "Content-Type": "application/json"
]
let parameters = ["text": "Hello from Pinnacle"] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.pinnacle.sh/messages/validate/sms")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```

> One API for RCS, iMessage, MMS, and SMS. Build, test, and scale every channel — send your first message in minutes, not weeks.