Send SMS

Send an SMS to one or more recipients.

POST /api/v1/sms/send · Permission: sms.send

Request

cURL

curl -X POST https://restlink23telecom.com/api/v1/sms/send \
  -H "X-API-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "to": [
    "+14155551234",
    "+447911123456"
  ],
  "message": "Your verification code is 847291",
  "sender_id": "MyApp"
}'

Node.js

const res = await fetch('https://restlink23telecom.com/api/v1/sms/send', {
  method: 'POST',
  headers: { 'X-API-Key': process.env.API_KEY, 'Content-Type': 'application/json' },
  body: JSON.stringify({
    "to": [
      "+14155551234",
      "+447911123456"
    ],
    "message": "Your verification code is 847291",
    "sender_id": "MyApp"
  }),
});

if (!res.ok) {
  const err = await res.json();
  throw new Error(`${err.error_code}: ${err.description}`);
}
const data = await res.json();
console.log(data);

Python

import os
import requests

res = requests.post(
    "https://restlink23telecom.com/api/v1/sms/send",
    headers={"X-API-Key": os.environ["API_KEY"]},
    json={
        "to": ["+14155551234", "+447911123456"],
        "message": "Your verification code is 847291",
        "sender_id": "MyApp"
    },
)
res.raise_for_status()
print(res.json())

PHP

<?php
$ch = curl_init('https://restlink23telecom.com/api/v1/sms/send');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST  => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER     => ['X-API-Key: ' . getenv('API_KEY'), 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS     => json_encode([
        'to' => ['+14155551234', '+447911123456'],
        'message' => 'Your verification code is 847291',
        'sender_id' => 'MyApp'
    ]),
]);

$response = curl_exec($ch);
$status   = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

if ($status !== 200) {
    throw new Exception("HTTP $status: $response");
}
$data = json_decode($response, true);
print_r($data);

Ruby

require "net/http"
require "json"

uri = URI("https://restlink23telecom.com/api/v1/sms/send")
req = Net::HTTP::Post.new(uri)
req["X-API-Key"] = ENV.fetch("API_KEY")
req["Content-Type"] = "application/json"
req.body = {
  to: ["+14155551234", "+447911123456"],
  message: "Your verification code is 847291",
  sender_id: "MyApp"
}.to_json

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(req) }
raise "HTTP #{res.code}: #{res.body}" unless res.is_a?(Net::HTTPSuccess)

puts JSON.parse(res.body)

Java

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

HttpClient client = HttpClient.newHttpClient();

HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create("https://restlink23telecom.com/api/v1/sms/send"))
    .header("X-API-Key", System.getenv("API_KEY"))
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString("""
        {
          "to": [
            "+14155551234",
            "+447911123456"
          ],
          "message": "Your verification code is 847291",
          "sender_id": "MyApp"
        }"""))
    .build();

HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());

Go

package main

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

func main() {
  payload := strings.NewReader(`{
  "to": [
    "+14155551234",
    "+447911123456"
  ],
  "message": "Your verification code is 847291",
  "sender_id": "MyApp"
}`)

  req, err := http.NewRequest("POST", "https://restlink23telecom.com/api/v1/sms/send", payload)
  if err != nil {
    panic(err)
  }
  req.Header.Set("X-API-Key", os.Getenv("API_KEY"))
  req.Header.Set("Content-Type", "application/json")

  res, err := http.DefaultClient.Do(req)
  if err != nil {
    panic(err)
  }
  defer res.Body.Close()

  data, _ := io.ReadAll(res.Body)
  fmt.Println(string(data))
}

.NET

using System.Text;

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key",
    Environment.GetEnvironmentVariable("API_KEY"));

var json = """
{
  "to": [
    "+14155551234",
    "+447911123456"
  ],
  "message": "Your verification code is 847291",
  "sender_id": "MyApp"
}
""";
var content = new StringContent(json, Encoding.UTF8, "application/json");
var response = await client.PostAsync("https://restlink23telecom.com/api/v1/sms/send", content);

response.EnsureSuccessStatusCode();
Console.WriteLine(await response.Content.ReadAsStringAsync());

Field	Type	Required	Description
to	string[]	Yes	1 to 100 phone numbers in E.164 format (+ optional, 6-15 digits)
message	string	Yes	Message text — encoding is detected automatically; max 10 SMS segments
sender_id	string	Yes	Sender ID for the message: 3-11 ASCII alphanumeric characters, first character cannot be a number
Idempotency-Key header	string	No	1-128 ASCII letters, numbers, _, -, . or :. Reuse it on a retry. Completed responses are retained for 24 hours and replayed byte-for-byte with Idempotent-Replayed: true; a replay is not a new send. X-Idempotency-Key is a legacy alias.

The API trims leading and trailing whitespace from to, message and sender_id before validation. Blank values, malformed phone numbers, over-10-segment messages, and invalid senders return 400.

Response

200 OK

{
  "status": true,
  "messages": [
    {"dnis": "+14155551234", "message_id": "api_42_1743667200123456789_a3f8b2c1d9e45f67", "segment_num": 1},
    {"dnis": "+447911123456", "message_id": "api_42_1743667200123456789_b7c4e8f1a2d3690b", "segment_num": 1}
  ],
  "results": [
    {"dnis": "+14155551234", "message_id": "api_42_1743667200123456789_a3f8b2c1d9e45f67", "segments": 1, "status": "accepted"},
    {"dnis": "+447911123456", "message_id": "api_42_1743667200123456789_b7c4e8f1a2d3690b", "segments": 1, "status": "accepted"}
  ],
  "summary": {
    "total_recipients": 2,
    "total_segments": 2,
    "total_cost": 0.02,
    "encoding": "GSM-7",
    "accepted_count": 2,
    "blocked_count": 0,
    "unpriced_count": 0,
    "queue_error_count": 0,
    "config_error_count": 0,
    "db_error_count": 0
  }
}

Field	Description
messages	Accepted messages only (backward-compatible array)
results	All recipients with their individual status
summary	Totals: accepted, blocked, errors, cost, detected encoding

Per-recipient statuses

results[].status	Meaning
accepted	Queued for delivery
blocked_country	Recipient’s country is in your blocked list
unpriced	Legacy/sandbox non-acceptance status retained for compatibility. Current live pricing misses are accepted and queued with a provisional local cost
queue_error	Sandbox simulator storage failure (sk_test_ only); live Redis enqueue failures stay accepted and are recovered from the durable outbox
config_error	SMS sending not configured on the account
db_error	The recipient’s outbox row could not be written

Atomic batches

Validation is all-or-nothing: one malformed recipient rejects the whole request. A blocked_country recipient has no message_id and is not queued. Missing or unmatched local pricing does not reject a valid live recipient: it is returned as accepted, queued with a provisional local cost that may be 0, and reconciled from the delivery report. If the database is briefly unavailable you get 500 DB_ERROR; no accepted recipient was persisted or sent, so retry the whole request.

Errors

HTTP	Code	Description
400	INVALID_BODY	Cannot parse request body
400	INVALID_TO	Missing or malformed recipient
400	INVALID_MESSAGE	Missing message or text over 10 SMS segments
400	INVALID_SENDER	Missing or invalid sender_id
400	TOO_MANY_RECIPIENTS	Over 100 recipients
400	INVALID_IDEMPOTENCY_KEY	Idempotency key is over 128 characters or has unsupported characters
403	NO_SMS_ACCESS	SMS not enabled on your account
403	CONFIG_ERROR	SMS credentials incomplete — contact support
403	WORKSPACE_NOT_AVAILABLE	Target workspace was deleted — use a live workspace
409	IDEMPOTENCY_KEY_REUSED	Same key was used with a different request body
409	IDEMPOTENCY_REQUEST_IN_PROGRESS	Same key is still processing — retry after it completes
429	RATE_LIMIT_EXCEEDED	Request exceeds your per-second message budget — retry later or reduce request rate
500	DB_ERROR	Could not queue (atomic rollback) — retry the whole request
500	IDEMPOTENCY_ERROR	Could not reserve the idempotency key — retry with the same key
503	SANDBOX_UNAVAILABLE / RATE_LIMIT_UNAVAILABLE / QUEUE_UNAVAILABLE	Sandbox simulator, rate limiter, or SMS queue temporarily unavailable — retry shortly

Pricing and balance are fail-open for direct API sends

New live processing does not create PRICING_UNAVAILABLE or a send-time 402 when Portal’s local pricing or balance data is missing. A valid recipient is accepted with a message_id; the local cost can be provisional until the delivery report arrives. Never retry an accepted message_id solely because its immediate cost is 0.

Delivery tracking

The send response confirms acceptance, not delivery. To learn whether the message reached the handset:

• Webhooks (recommended): receive a delivery report on your server the moment the carrier reports it.
• Polling: call GET /sms/status/:message_id until the status is final.