SMS & Voice API Documentation | Bulk Blaster Developer Docs

SMS API

SMS API Documentation

Send SMS to India and 200+ countries via our high-performance Google Cloud Run infrastructure.

https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app

AUTH Authentication

All SMS API requests require your API key. Include it in the request body as apiKey or in the Authorization header:

// Option 1: In request body
{ "apiKey": "YOUR_API_KEY" }

// Option 2: In header
Authorization: Bearer YOUR_API_KEY

Find your API key in Dashboard → API Keys after logging in.

POST /send-sms Send Single SMS (India)

Send a single SMS to an Indian phone number.

Parameters

Parameter	Type	Required	Description
`apiKey`	string	Yes	Your API key
`phone`	string	Yes	10-digit number (without country code)
`message`	string	Yes	Message content (max 160 chars)
`senderId`	string	No	Custom sender ID (max 11 chars)

Example Request

cURLJavaScriptPython

curl -X POST "https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/send-sms" \
  -H "Content-Type: application/json" \
  -d '{
    "apiKey": "YOUR_API_KEY",
    "phone": "9876543210",
    "message": "Hello from Bulk Blaster API!"
  }'

const res = await fetch("https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/send-sms", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    apiKey: "YOUR_API_KEY",
    phone: "9876543210",
    message: "Hello from Bulk Blaster API!"
  })
});
const data = await res.json();

import requests

url = "https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/send-sms"
payload = {
    "apiKey": "YOUR_API_KEY",
    "phone": "9876543210",
    "message": "Hello from Bulk Blaster API!"
}
response = requests.post(url, json=payload)
print(response.json())

Response

{ "success": true, "message": "SMS queued for delivery", "coins_used": 2, "coins_remaining": 98 }

POST /send-bulk-sms Bulk SMS (India)

Send SMS to multiple Indian phone numbers in a single request.

Parameters

Parameter	Type	Required	Description
`apiKey`	string	Yes	Your API key
`recipients`	array	Yes	Array of 10-digit phone numbers
`message`	string	Yes	Message content (max 160 chars)
`senderId`	string	No	Custom sender ID

Example Request

curl -X POST "https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/send-bulk-sms" \
  -H "Content-Type: application/json" \
  -d '{
    "apiKey": "YOUR_API_KEY",
    "recipients": ["9876543210", "9876543211", "9876543212"],
    "message": "Hello from Bulk Blaster!"
  }'

Response

{ "success": true, "message": "Bulk SMS sent to 3 recipients", "coins_used": 6, "coins_remaining": 94 }

POST /send-international-sms International SMS (200+ countries)

Send SMS to international phone numbers. Supports Flash SMS mode.

Parameters

Parameter	Type	Required	Description
`apiKey`	string	Yes	Your API key
`phone`	string	Yes	Full number with country code (e.g. +61488861655)
`message`	string	Yes	Message content (max 160 chars)
`isFlash`	boolean	No	Set `true` for flash SMS (default: false)

Example Request

curl -X POST "https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/send-international-sms" \
  -H "Content-Type: application/json" \
  -d '{
    "apiKey": "YOUR_API_KEY",
    "phone": "+61488861655",
    "message": "Hello from Bulk Blaster International!",
    "isFlash": false
  }'

Response

{ "success": true, "message": "International SMS sent successfully", "coins_used": 16, "coins_remaining": 84 }

GET /account-balance Check Balance

Check your current account balance (remaining SMS/Voice coins).

Example Request

curl -X GET "https://bulkblaster-india-sms-lc-290441563653.asia-south1.run.app/account-balance" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{ "success": true, "balance": 100, "currency": "coins" }

VOICE API

Voice API Documentation

Make TTS calls, upload voice files, and blast voice messages to thousands.

POST /api/tts-call Text-to-Speech Call

https://bulkblaster-ttsvoicecall-290441563653.asia-south1.run.app

Convert text to speech and make an automated voice call to any Indian number.

Headers

Content-Type: application/json
x-api-key: YOUR_API_KEY

Parameters

Parameter	Type	Required	Description
`callee`	string	Yes	10-digit Indian phone number
`text`	string	Yes	Message to speak (max 250 chars)
`language`	string	No	EN, HI, TE, TA, KN, ML, BN, GU, MR, PA
`accent`	string	No	91 (Indian), 1 (US), 44 (UK), 61 (AU)
`ssmlGender`	integer	No	1 = Male, 2 = Female (default)
`speakingRate`	float	No	0.8 (slow), 1.0 (normal), 1.2 (fast)

Example Request

curl -X POST "https://bulkblaster-ttsvoicecall-290441563653.asia-south1.run.app/api/tts-call" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "callee": "9876543210",
    "text": "Hello, this is a test call from Bulk Blaster",
    "language": "EN",
    "accent": "91",
    "ssmlGender": 2,
    "speakingRate": 1.0
  }'

Response

{ "success": true, "message": "TTS call initiated successfully", "coins_used": 3, "coins_remaining": 97 }

POST /api/upload-voice Upload Voice File

https://bulkblaster-nextgenvoice-290441563653.asia-south1.run.app

Upload a voice recording to be used for voice blast calls.

Headers

Content-Type: application/json
x-api-key: YOUR_API_KEY

Parameters

Parameter	Type	Required	Description
`fileName`	string	Yes	Name of voice file (e.g. "welcome.mp3")
`base64Data`	string	Yes	Base64 encoded file data (max 5MB)

Example Request

curl -X POST "https://bulkblaster-nextgenvoice-290441563653.asia-south1.run.app/api/upload-voice" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "fileName": "welcome_message.mp3",
    "base64Data": "BASE64_ENCODED_FILE_DATA"
  }'

Response

{ "success": true, "fileId": "FILE123456789", "message": "Voice file uploaded successfully" }

POST /api/make-voice-call Voice Blast Call

https://bulkblaster-nextgenvoice-290441563653.asia-south1.run.app

Make a voice call using an uploaded voice file.

Headers

Content-Type: application/json
x-api-key: YOUR_API_KEY

Parameters

Parameter	Type	Required	Description
`callee`	string	Yes	Recipient number with country code (e.g. "919876543210")
`fileId`	string	Yes	ID of the uploaded voice file

Example Request

curl -X POST "https://bulkblaster-nextgenvoice-290441563653.asia-south1.run.app/api/make-voice-call" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "callee": "919876543210",
    "fileId": "FILE123456789"
  }'

Response

{ "success": true, "callId": "CALL123456789", "message": "Voice call initiated successfully", "coins_used": 2, "coins_remaining": 98 }

Response Codes

Our APIs use standard HTTP status codes:

Code	Description
`200 OK`	Request was successful
`400 Bad Request`	Missing or invalid parameters
`401 Unauthorized`	Invalid or missing API key
`403 Forbidden`	Insufficient balance or permission denied
`429 Too Many Requests`	Rate limit exceeded
`500 Server Error`	Internal server error

Rate Limiting

To ensure fair usage and system stability:

Plan	Limit
Starter	10 requests/minute
Business	60 requests/minute
Premium	200 requests/minute

Exceeding limits returns 429 Too Many Requests. Wait before retrying.

Best Practices

Secure your keys

Never expose API keys in client-side code or public repos

Retry with backoff

Use exponential backoff for failed requests

Validate inputs

Validate phone numbers before sending

Monitor usage

Cache balance to avoid unnecessary API calls