Send to Multiple Numbers API

Send the same WhatsApp message to several phone numbers and groups in one request. Use it for small broadcasts such as newsletters, offers and announcements.

Wbiztool creates one message per recipient and returns a msg_id for each, so you can check their status individually.

Quick example#

curl -X POST https://wbiztool.com/api/v1/send_msg/multi/ \
  -H "Content-Type: application/json" \
  -d '{
    "client_id": 12345,
    "api_key": "YOUR_API_KEY",
    "whatsapp_client": 678,
    "msg_type": 0,
    "country_code": "91",
    "phone": "9876543210,9812345670,Sales Team Mumbai",
    "msg": "Our Diwali sale starts tomorrow. Get 20% off on all orders!"
  }'

import requests

response = requests.post(
    "https://wbiztool.com/api/v1/send_msg/multi/",
    json={
        "client_id": 12345,
        "api_key": "YOUR_API_KEY",
        "whatsapp_client": 678,
        "msg_type": 0,
        "country_code": "91",
        "phone": ",".join(["9876543210", "9812345670", "Sales Team Mumbai"]),
        "msg": "Our Diwali sale starts tomorrow. Get 20% off on all orders!",
    },
    timeout=60,
)
result = response.json()  # read the body even when the HTTP code is 400

if result.get("status") == 1:
    for item in result["messages"]:
        print(item["contact"], "->", item["msg_id"])
else:
    print("Failed:", result.get("message", "no message in response"))

// Node.js 18+ (built-in fetch). Save as .mjs to use top-level await.
const response = await fetch("https://wbiztool.com/api/v1/send_msg/multi/", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    client_id: 12345,
    api_key: "YOUR_API_KEY",
    whatsapp_client: 678,
    msg_type: 0,
    country_code: "91",
    phone: ["9876543210", "9812345670", "Sales Team Mumbai"].join(","),
    msg: "Our Diwali sale starts tomorrow. Get 20% off on all orders!",
  }),
});
const result = await response.json(); // read the body even when the HTTP code is 400

if (result.status === 1) {
  for (const item of result.messages) {
    console.log(item.contact, "->", item.msg_id);
  }
} else {
  console.error("Failed:", result.message ?? "no message in response");
}

<?php
$payload = [
    'client_id'       => 12345,
    'api_key'         => 'YOUR_API_KEY',
    'whatsapp_client' => 678,
    'msg_type'        => 0,
    'country_code'    => '91',
    'phone'           => implode(',', ['9876543210', '9812345670', 'Sales Team Mumbai']),
    'msg'             => 'Our Diwali sale starts tomorrow. Get 20% off on all orders!',
];

$ch = curl_init('https://wbiztool.com/api/v1/send_msg/multi/');
curl_setopt_array($ch, [
    CURLOPT_POST           => true,
    CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS     => json_encode($payload),
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT        => 60,
]);
$result = json_decode(curl_exec($ch), true);
curl_close($ch);

if (($result['status'] ?? 0) === 1) {
    foreach ($result['messages'] as $item) {
        echo $item['contact'] . ' -> ' . $item['msg_id'] . PHP_EOL;
    }
} else {
    echo 'Failed: ' . ($result['message'] ?? 'no message in response');
}

Replace 12345, YOUR_API_KEY and 678 with your own values. See Authentication for where to find them.

Request parameters#

curl -X POST https://wbiztool.com/api/v1/send_msg/multi/ \
  -H "Content-Type: application/json" \
  -d '{
    "client_id": 12345,
    "api_key": "YOUR_API_KEY",
    "whatsapp_client": 678,
    "msg_type": 1,
    "country_code": "91",
    "phone": "9876543210,9812345670",
    "img_url": "https://example.com/offers/diwali-sale.jpg",
    "msg": "Our Diwali sale starts tomorrow."
  }'

How recipients are read#

Wbiztool splits phone on commas, trims spaces around each item and then decides what each item is:

• Only digits (a leading + or leading zeros are fine): treated as a phone number. country_code is added unless the number already starts with it, then the number must be 6 to 15 digits long.
• Anything else: treated as a WhatsApp group name, found the same way as in Send to group.
• A group whose name is only digits (for example 2024) is treated as a phone number, and group names containing commas can't be sent from this endpoint. Use Send to group for those.

Other things to know:

• Numbers that are too short or too long after adding the country code are skipped silently. They don't appear in the response and don't get a msg_id.
• Duplicates aren't removed. A number listed twice gets two messages.
• If a local number happens to start with the same digits as country_code (for example 9123456780 with country_code 91), the code isn't added. Send such numbers with the country code already included (919123456780).
• Image and file URLs aren't checked when you call the API. They're downloaded when each message is sent, so a broken link makes the messages fail later rather than the request. The same send-time rules as Send message apply: images over 16 MB and videos over 64 MB fail, WAV and OGG audio isn't supported, and files (msg_type 2) without a supported extension get .pdf added. See Sending images and files.

Credits#

The whole batch is checked against your remaining credits before anything is created. Every non-empty item in phone counts, including items that are later skipped. If the count is higher than your remaining credits, no messages are created and you get:

{
  "message": "Not enough credits: 120 messages requested, 85 credits remaining",
  "status": 0
}

Messages that are queued but not yet sent also count against your remaining credits. Split large lists into smaller requests or top up your plan. For big campaigns, upload a spreadsheet from the Campaigns page instead.

Response#

A successful request returns HTTP 200:

{
  "msg_ids": [9817263, 9817264, 9817265],
  "messages": [
    { "msg_id": 9817263, "contact": "919876543210", "is_group": false },
    { "msg_id": 9817264, "contact": "919812345670", "is_group": false },
    { "msg_id": 9817265, "contact": "Sales Team Mumbai", "is_group": true }
  ],
  "message": "Successfully created 3 messages",
  "status": 1
}

Compare messages with the list you sent to find skipped numbers, and check that is_group is false for every item you meant as a phone number.

Errors#

Most errors return HTTP 200 with status set to 0, so always check status in the body. Except for the HTTP 400 and 403 errors, responses (successful ones included) are JSON sent with Content-Type: text/html, so parse the body yourself instead of relying on automatic JSON detection (for example in no-code tools):

{ "message": "Invalid whatsapp client", "status": 0 }

Tips#

• Send phone as a string: join your list with commas. A JSON array returns {}.
• Don't use the Python client's send_bulk_messages for now: it sends the list as phones, which this endpoint ignores. Call the endpoint directly as in the examples above.
• Track each message: save every msg_id from messages, or pass a webhook to be notified as each one is sent or fails.
• Keep your number connected: every message is sent from your WhatsApp number, so it must stay connected in WhatsApp settings until the whole batch has gone out.
• Different text per person: this endpoint sends the same msg to everyone. Call Send message once per recipient to personalise each message.