SMS & RCS API documentation

The CheapBulkSMS API lets you send SMS and RCS messages to any Indian mobile number programmatically — no DLT registration, flat ₹0.80 per SMS and ₹1.50 per RCS message. All requests are JSON over HTTPS.

Base URL
https://cheap-bulk-sms-india.com

Endpoints
POST /api/v1/sms        Send SMS or RCS
POST /api/v1/reports    Fetch delivery statuses

Create an API token from your dashboard under Dashboard → API. Tokens are shown once at creation — store them securely and never expose them in client-side code. Pass the token on every request in the x-api-key header (or as Authorization: Bearer).

x-api-key: cbs_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Requests without a valid token return 401 Unauthorized. Revoking a token in the dashboard disables it immediately.

Send one message to up to thousands of numbers in a single call. Numbers can be 10-digit Indian mobiles (we prefix +91) or include the country code; duplicates are removed automatically.

curl -X POST https://cheap-bulk-sms-india.com/api/v1/sms \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_TOKEN" \
  -d '{
    "numbers": "9876543210, 9123456780",
    "message": "FLAT 50% OFF this weekend at MyStore. Shop now: https://mystore.in",
    "senderId": "MYSTOR"
  }'

Node.js

const res = await fetch("https://cheap-bulk-sms-india.com/api/v1/sms", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "x-api-key": process.env.CBS_API_KEY,
  },
  body: JSON.stringify({
    numbers: ["9876543210", "9123456780"],
    message: "Your order #4821 has shipped!",
  }),
});
const data = await res.json();
console.log(data.sent, data.messageIds);

Python

import requests

resp = requests.post(
    "https://cheap-bulk-sms-india.com/api/v1/sms",
    headers={"x-api-key": "YOUR_TOKEN"},
    json={
        "numbers": "9876543210,9123456780",
        "message": "Your OTP is 482910. Valid for 10 minutes.",
    },
)
print(resp.json())

Success response

{
  "status": "success",
  "total": 2,
  "sent": 2,
  "failed": 0,
  "messageIds": ["2412170930123456", "2412170930123457"],
  "failures": [],
  "invalidNumbers": []
}

Keep the messageIds — you'll use them to query delivery reports.

To send a different message to each number — names, order IDs, amounts, links — pass a recipients array instead of numbers. Each entry carries its own final message text, so you control the templating in your own system.

curl -X POST https://cheap-bulk-sms-india.com/api/v1/sms \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_TOKEN" \
  -d '{
    "recipients": [
      { "phone": "9876543210", "message": "Hi Rahul, your EMI of Rs 4,500 is due on 20 Oct." },
      { "phone": "9123456780", "message": "Hi Priya, your EMI of Rs 7,200 is due on 22 Oct." }
    ],
    "senderId": "MYFINC"
  }'

RCS delivers rich, branded messages on supported Android devices at ₹1.50 per message. Use the same endpoint with "type": "rcs". Recipients whose handset can't receive RCS are returned in failures — resend those over SMS for full coverage.

curl -X POST https://cheap-bulk-sms-india.com/api/v1/sms \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_TOKEN" \
  -d '{
    "numbers": "9876543210,9123456780",
    "message": "Diwali Mega Sale is live! Up to 60% off storewide.",
    "type": "rcs"
  }'

{
  "status": "success",
  "total": 2,
  "sent": 1,
  "failed": 1,
  "messageIds": ["2412170931987654"],
  "failures": [
    { "phone": "919123456780", "reason": "RCS not accepted (status -42)" }
  ],
  "invalidNumbers": []
}

SMS fallback pattern: collect the phones from failures and POST them again with "type": "sms".

Query the delivery status of previously sent messages using the messageIds returned by the send call. Up to 5,000 IDs per request.

curl -X POST https://cheap-bulk-sms-india.com/api/v1/reports \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_TOKEN" \
  -d '{ "messageIds": ["2412170930123456", "2412170930123457"] }'

{
  "status": "success",
  "statuses": {
    "2412170930123456": "delivered",
    "2412170930123457": "pending"
  }
}

Billing is per segment. Plain English (GSM-7) messages fit 160 characters in one segment, 153 per segment when longer. Unicode messages — Hindi, Marathi, emoji, the ₹ symbol — fit 70 characters per single segment, 67 when longer.

A 200-character English message = 2 segments = 2 × ₹0.80. Keep OTPs and alerts under 160 GSM characters for single-segment cost.

{
  "status": "error",
  "error": "Invalid or missing API key. Pass it as the x-api-key header."
}

• Store tokens server-side only — never ship them in mobile apps or browser code.
• Keep messageIds with your own order/user records so delivery reports map back cleanly.
• Poll reports no more than once a minute; most deliveries confirm within seconds.
• For OTPs, send one number per call for the lowest latency; for marketing, batch freely.
• Honour opt-outs: maintain your own suppression list and filter before calling the API.