# Messages

# Before You Start

There are two types of SMS messages, determined by their length:

Simple SMS – A message containing up to 160 characters.
Concatenated SMS – A message containing up to 39,015 characters, which is delivered as a single message on the recipient’s device.
These are sent as multiple SMS segments, with each 153-character segment being charged separately.

The GoSMS platform automatically detects when a message exceeds 153 characters. It will display an informational message showing the total number of SMS segments that will be billed.

note

GoSMS uses the Latin ISO-8859-1 character encoding, where each character occupies 1 byte.

"Special Characters & Encoding"

If your message contains special characters (e.g., diacritics, “, –, ˜, ™, €, ^, /, {, }, \, [, ], |) that are not part of the standard Latin alphabet, the system will switch to the extended character set.

In this case:

Each character is encoded using 2 bytes.
The maximum length is reduced to 70 characters for a single SMS.
Concatenated messages are limited to 63 characters per segment.

# Sending a Message

To send an SMS, make a POST request to the /message/send endpoint.

# Parameters

Parameter	Required?	Description
`recipient`	yes	The mobile phone number of the recipient. Format requirements: • National (Romania): `07PPXXXXXX`, `407PPXXXXXX`. • For international numbers, add the 00 prefix: `00359XXXXXXXXX`.
`message`	yes	The text of the SMS message.
`sender`	no	The sender of the message. Must be pre-approved and configured by a GoSMS representative. • Alphanumeric senders may not be supported by all operators. • If missing or invalid, the default short number will be used.
`scheduleDatetime`	no	The date and time when the SMS should be sent. Accepted formats: `YYYY-MM-DDTHH:MM:SS.mmmZ` or `YYYY-MM-DD HH:MM:SS`. If missing or invalid, the server’s current time will be used.
`validity`	no	Validity period in minutes. If provided and greater than 0, this defines how long the message remains valid from the scheduled date and time. If not delivered within this period, it will expire and will not be charged.

# Code Samples

curl -X POST "https://api.gosms.ro/v1/message/send" \
     -H "X-Authorization: [YOUR_API_KEY]" \
     -H "Content-Type: application/json" \
     -d '{
           "recipient": "0712345678",
           "message": "This is a test message."
         }'

try {
    const res = await fetch("https://api.gosms.ro/v1/message/send", {
        method: "POST",
        headers: {
            "X-Authorization": "[YOUR_API_KEY]",
            "Content-Type": "application/json"
        },
        body: JSON.stringify({
            recipient: "0712345678",
            message: "This is a test message."
        })
    })
    const json = await res.json()
    console.log(json)
} catch(err) {
    console.log(err)
}

<?php

$apiKey = "[YOUR_API_KEY]";
$url = "https://api.gosms.ro/v1/message/send";

$data = [
    "recipient" => "0712345678",
    "message" => "This is a test message."
];

$ch = curl_init($url);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "X-Authorization: $apiKey",
    "Content-Type: application/json"
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));

$response = curl_exec($ch);
curl_close($ch);

echo $response;

# Response

On success, the endpoint returns a JSON response like the following:

{
  "success": true,
  "messageId": "dea3535d-2b1e-4c05-b3ea-6879c8d2516c",
  "balanceDeduction": "0.03",
  "currency": "EUR"
}