Blast SMS API

Introduction

The Blast SMS REST API lets you send SMS, check delivery and manage contacts from your own application. All requests and responses use JSON over HTTPS.

Authentication

Create an API token under Developers in your dashboard and send it in the Authorization header on every request. Keep it secret; regenerate it if it leaks.

Rate limit: 120 requests per minute per token.

Responses & errors

Successful calls return "status": "success" with a data object. Errors return "status": "error" and a human-readable message.

{ "status": "error", "message": "Insufficient SMS balance: 400 units needed, 120 available." }

Message statuses: queued → sent → delivered, or failed / cancelled. Messages the network rejects at submission are refunded automatically.

Send SMS

Send one message to one or many numbers (up to 10,000 per request). Numbers can be local (07…, 01…) or international (2547…).

curl -X POST https://blastsms.site/api/v1/sms/send \
  -H "Authorization: Bearer YOUR_API_TOKEN" \
  -H "Accept: application/json" -H "Content-Type: application/json" \
  -d '{"sender_id":"BLASTSMS","phone":"0712345678,0798765432","message":"Hello from Blast SMS!"}'

{
  "status": "success",
  "message": "Message queued for delivery",
  "data": {
    "campaign_id": "k2j4h5g6f7d8s",
    "status": "queued",
    "recipients": 2,
    "units": 2,
    "cost": 0.70,
    "balance": 998,
    "invalid": [],
    "blacklisted": 0,
    "messages": [ { "uid": "a1b2c3…", "to": "254712345678", "status": "queued", "parts": 1 } ]
  }
}

Send to contact groups

Send a personalised campaign to one or more contact groups. Use tags {first_name} {last_name} {name} {phone}.

{ "name": "December promo", "sender_id": "BLASTSMS", "group_ids": ["6065ecdc9184a"],
  "message": "Hi {first_name}, enjoy 20% off this week!", "schedule_time": "2026-12-20 10:00" }

Get SMS length / cost

{ "message": "Hello 👋", "phone": "0712345678,0722000000" }
→ { "status": "success", "data": { "encoding": "unicode", "length": 8, "parts": 1, "recipients": 2, "units": 2, "rate": 0.35, "cost": 0.7, "balance": 1000, "sufficient": true } }

Message status

{ "status": "success", "data": { "uid": "a1b2c3…", "to": "254712345678", "from": "BLASTSMS", "status": "delivered",
  "parts": 1, "units": 1, "cost": 0.35, "sent_at": "2026-10-22T10:00:02+03:00", "delivered_at": "2026-10-22T10:00:05+03:00" } }

List messages

Filters: status, phone, campaign_id, from_date, to_date, per_page (max 200), page. Responses include a meta pagination object.

Campaigns

Cancelling a scheduled or queued campaign refunds every unsent message.

Simple HTTP (GET) send

For systems that can only call a URL, pass the token as api_key:

Balance

{ "status": "success", "data": { "sms_balance": 1250, "rate": 0.35, "currency": "KES", "estimated_value": 437.5 } }

Profile

Sender IDs

Sender IDs you can send with right now.

Transactions

Ledger of top-ups, charges and refunds in SMS units.

Contact groups

POST /contact-groups   { "name": "VIP customers" }
→ { "status": "success", "data": { "uid": "6065ecdc9184a", "name": "VIP customers", "status": "active", "contacts": 0 } }

Contacts

Templates

Delivery webhooks

Set a webhook URL under Developers. Whenever a message status changes we POST JSON to it. Verify the X-Signature header: HMAC-SHA256 of the raw body, keyed with the SHA-256 hash of your API token. Failed deliveries are retried up to 5 times.

{ "event": "sms.status", "uid": "a1b2c3…", "to": "254712345678", "from": "BLASTSMS", "status": "delivered",
  "parts": 1, "cost": 0.35, "client_reference": "order-1042", "delivered_at": "2026-10-22T10:00:05+03:00" }

Code samples

<?php
$ch = curl_init('https://blastsms.site/api/v1/sms/send');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer YOUR_API_TOKEN',
        'Accept: application/json',
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([
        'sender_id' => 'BLASTSMS',
        'phone' => '0712345678',
        'message' => 'Hello World! This is a test message.',
    ]),
]);
$response = json_decode(curl_exec($ch), true);
curl_close($ch);
print_r($response);

import requests

r = requests.post(
    "https://blastsms.site/api/v1/sms/send",
    headers={"Authorization": "Bearer YOUR_API_TOKEN", "Accept": "application/json"},
    json={"sender_id": "BLASTSMS", "phone": "0712345678", "message": "Hello World!"},
    timeout=30,
)
print(r.json())

const res = await fetch('https://blastsms.site/api/v1/sms/send', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer YOUR_API_TOKEN',
    Accept: 'application/json',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ sender_id: 'BLASTSMS', phone: '0712345678', message: 'Hello World!' }),
});
console.log(await res.json());

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create("https://blastsms.site/api/v1/sms/send"))
    .header("Authorization", "Bearer YOUR_API_TOKEN")
    .header("Accept", "application/json")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString(
        "{\"sender_id\":\"BLASTSMS\",\"phone\":\"0712345678\",\"message\":\"Hello World!\"}"))
    .build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());