WAChecker Public API

A simple, no-auth REST API to check whether phone numbers are registered on WhatsApp. Build automations, AI agents, and integrations without signing up or paying.

POST up to 10 phone numbers. You receive a request_id immediately. Validation happens asynchronously.

curl -X POST https://api.bulknumberchecker.com/api/v1/check \
  -H "Content-Type: application/json" \
  -d '{
    "numbers": ["+6281234567890", "+14155552671"],
    "default_country": "ID"
  }'

Example response:

{
  "request_id": "req_abc123xyz",
  "total": 2,
  "cached": 0,
  "pending": 2,
  "status": "pending",
  "status_url": "https://api.bulknumberchecker.com/api/v1/check/req_abc123xyz",
  "rate_limit": {
    "limit": 5,
    "remaining": 4,
    "reset_at": "2026-04-16T00:00:00.000Z"
  }
}

Poll every 3–5 seconds until status is completed or failed. Poll calls do not consume quota.

curl https://api.bulknumberchecker.com/api/v1/check/req_abc123xyz

Example completed response:

{
  "request_id": "req_abc123xyz",
  "status": "completed",
  "progress": { "total": 2, "completed": 2, "cached": 0 },
  "eta_seconds": null,
  "results": [
    {
      "input": "+6281234567890",
      "phoneNumber": "+6281234567890",
      "countryCode": "ID",
      "countryName": "Indonesia",
      "whatsappStatus": "valid"
    },
    {
      "input": "+14155552671",
      "phoneNumber": "+14155552671",
      "countryCode": "US",
      "countryName": "United States",
      "whatsappStatus": "invalid"
    }
  ]
}

Once status is completed, download results as a CSV file. Returns 404 {error:"not_ready"} if called before completion.

curl -o results.csv \
  https://api.bulknumberchecker.com/api/v1/check/req_abc123xyz/csv

CSV columns: Input, Phone Number, Country Code, Country, WhatsApp Status

Code examples

// JavaScript (fetch) — submit, poll, and print results
const API = "https://api.bulknumberchecker.com";

async function checkNumbers(numbers) {
  // Step 1: submit
  const res = await fetch(`${API}/api/v1/check`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ numbers }),
  });
  if (!res.ok) throw new Error(`Submit failed: ${res.status}`);
  const { request_id } = await res.json();

  // Step 2: poll until completed
  while (true) {
    const poll = await fetch(`${API}/api/v1/check/${request_id}`);
    const data = await poll.json();

    if (data.status === "completed") return data.results;
    if (data.status === "failed")   throw new Error("Validation failed");

    await new Promise((r) => setTimeout(r, 3000)); // wait 3s
  }
}

checkNumbers(["+6281234567890", "+14155552671"])
  .then((results) => console.log(results))
  .catch(console.error);

OpenAPI 3.1 Specification

The full machine-readable API spec is available at /openapi.json. Load it into any OpenAPI-compatible tool (Postman, Insomnia, Stoplight, Scalar, etc.) or feed it to an AI agent as a tool definition.