usando System;
using System.Net;
using System.IO;
using System.Web;

protected void SendMessage()
{
string nome de utilizador="+4540818824″;
string password="12345″;
string tophonenumberwithcountrycode="+4540818824″;
string fromMax11Char="Pai Natal";
string theMessage = "Olá mundo! Posso enviar caracteres especiais como æ ø e å";

string pathtouse = "https://api.suresms.com/Script/SendSMS.aspx?login=" + nome de utilizador + "&password=" + password +
"&to=" + tophonenumberwithcountrycode + "&from=" + fromMax11Char + "&Text=" + WebUtility.UrlEncode(theMessage);

/* Chamar o caminho */
WebRequest wrGETURL;
wrGETURL = WebRequest.Create(pathtouse);
Fluxo objStream;
objStream = wrGETURL.GetResponse().GetResponseStream();
}

$message = "A sua mensagem";

$curlUrl = "https://api.suresms.com/script/sendsms.aspx?login=USER&password=PASSWORD&to=+". $phone ."&from=SENDER&message=". urlencode ( $message );

ob_start();
$curl = curl_init();
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_URL, $curlUrl);
$result = curl_exec ($curl);

$hs = curl_getinfo($curl, CURLINFO_HEADER_SIZE);
$header = substr($result, 0, $hs);
$body = substr($result, $hs);

curl_close ($curl);
ob_end_clean();

if(0 == strcmp(substr($header, 0, 13), "Message sent.") )
{
   /A sms foi enviada
}
else
{
   /A sms NÃO foi enviada
}

curl -G --data-urlencode --data-urlencode https://api.suresms.com/script/sendsms.aspx?to=+4512345678&body=helo world

$ToDoDirectory = 'C:\Temp\Inbox'
$FinishedDirectory = 'C:\Temp\SentBox'
$urlTemplate = 'https://api.suresms.com/Script/SendSMS.aspx?login={0}&password={1}&to={2}&Text={3}'
$smsGateLogin = 'xxxx'
$smsGatePassword = 'yyyyy'

 $filesToDo = @([ System.IO.Directory]::EnumerateFiles($ToDoDirectory,'*.sms', [ System.IO.SearchOption]::TopDirectoryOnly))
foreach ($fileToDo in $filesToDo)
{

$smsNumber = get-content -path $fileToDo |Select-Object -First 1
$smsText = get-content -path $fileToDo |Select-Object -Last 1

$uri = [String]::Format($urlTemplate, $smsGateLogin, $smsGatePassword, $smsNumber, $smsText)
$requestResult = Invoke-WebRequest -Method get -Uri $uri


$destSmsFile = [System.IO.Path]::Combine($FinishedDirectory, [ System.IO.Path]::GetFileName($fileToDo))
[ System.IO.File]::Move($fileToDo, $destSmsFile)
}

importar json
pedidos de importação
tempo de importação

auth_headers = {'Accept': 'application/json'}
auth_payload = {
"grant_type": "password",
"userName": "******",
"password": "*******"
}

r = requests.post("https://api.suresms.com/json/token", data=auth_payload, headers=auth_headers)
auth_response = json.loads(r.text)
time.sleep(1)

print "A enviar um SMS!"
carga útil = {
"MessageID": "etId",
"MessageText": "Teste sexta-feira, 3 de novembro. Agora é o dia J",
"ToPhoneNumbers": "4520xxxx;4529xxxx",
"SenderID": "Allerup",
"SendAsFlash": Falso,
"HasCallBackURL": "",
"RequiredDeliveryUTCDateTime": "2017-11-03T09:06:00.810Z",
"ScheduleDaily": Falso,
"ScheduleDailyExceptWeekend": Falso,
"ScheduleWeekly": Falso,
"ScheduleMonthly": Falso,
"ScheduleYearly": False}

headers = {'Authorisation': 'Bearer ' + str(auth_response["access_token"])}

r = requests.post("https://api.suresms.com/json/api/Message", data=payload, headers=headers)
print(r.text)

Para mais exemplos, consultar https://developer.suresms.com.