WhatsApp Number Detection — Bulk Check via Platform or API | CheckNumber.AI

WhatsApp Number Detection API — Step-by-Step Integration Guide

Verifying WhatsApp registration at scale is essential for marketing list cleaning, fraud detection, lead qualification, and CRM data validation. This guide walks you through integrating CheckNumber.AI’s WhatsApp bulk verification API, with code examples in curl, Python, and Node.js.

How It Works

Production checks run as batch tasks: upload a file, poll status, download results — not one synchronous HTTP call per phone number. This approach handles large-scale verifications efficiently.

Official reference: WhatsApp Checker — bulk registration.

Submit task

POST https://api.checknumber.ai/v1/tasks

Example — curl:

curl --location 'https://api.checknumber.ai/v1/tasks' \
--header 'X-API-Key: API-KEY' \
--form 'file=@"./numbers.txt"' \
--form 'task_type="ws"'

Example — Python:

import requests

url = "https://api.checknumber.ai/v1/tasks"
headers = {"X-API-Key": "YOUR_API_KEY"}

with open("numbers.txt", "rb") as f:
    files = {"file": f, "task_type": (None, "ws")}
    response = requests.post(url, headers=headers, files=files)
    
print(response.json())
# Output: {"task_id": "xyz123", "status": "pending", "total": 1000}

Example — Node.js:

const FormData = require('form-data');
const fs = require('fs');
const axios = require('axios');

const form = new FormData();
form.append('file', fs.createReadStream('numbers.txt'));
form.append('task_type', 'ws');

axios.post('https://api.checknumber.ai/v1/tasks', form, {
  headers: {
    ...form.getHeaders(),
    'X-API-Key': 'YOUR_API_KEY'
  }
}).then(res => console.log(res.data))
  .catch(err => console.error(err.message));

Poll status

POST https://api.checknumber.ai/v1/gettasks

curl --location 'https://api.checknumber.ai/v1/gettasks' \
--header 'X-API-Key: API-KEY' \
--form 'task_id="TASK_ID"'

Result columns

Common Errors & Troubleshooting

FAQ

Q: How long does bulk verification take? A: Typically 5-30 seconds for files up to 100,000 numbers, depending on queue load.

Q: What’s the minimum and maximum file size? A: Minimum is 1 number, maximum is 50MB (usually ~5M numbers in CSV format).

Q: Are credits deducted only on successful checks? A: Yes. Only successfully verified results consume credits. Failed rows don’t charge.

Next Steps

• Ready to start? Sign up for 1,000 free checks →
• See full pricing: Pricing Page →
• Full API docs: API Documentation →

Integration notes

1. One number per line; include country code in E.164.
2. Poll until status is exported, then use result_url.
3. See official documentation.
4. Pricing: pricing.