WhatsApp Number Validator API — Silent Existence Check

Why silent validation matters

Naive WhatsApp verification scripts (including most open-source GitHub projects) send a message or open a chat session to test existence. This leaves fingerprints — the target can see a read receipt, an "online" status, or a message preview. That is unacceptable for most commercial workflows. This endpoint performs a directory-level query against the WhatsApp user registry without any visible interaction with the target account.

Request and response

GET https://whatsapp-proxy.checkleaked.cc/number-simple/13105551234
x-rapidapi-key: <your-direct-purchase-key>

# RapidAPI marketplace variant:
# GET https://whatsapp-data1.p.rapidapi.com/number-simple/13105551234
# x-rapidapi-key:  <your-rapidapi-key>
# x-rapidapi-host: whatsapp-data1.p.rapidapi.com

{
  "number": "13105551234",
  "isWAContact": true,
  "isBusiness": false,
  "date": "2026-04-24T12:34:56Z"
}

Need full profile (about, picture)? Use /number/{number} instead.

Use cases

• SMS/WhatsApp OTP routing — pick the right channel based on whether the number is on WhatsApp. Save 70-90% on SMS cost for numbers that have WhatsApp.
• Signup fraud detection — reject numbers that aren't on WhatsApp during account creation for WA-first products.
• Cold outreach compliance — skip personal-account numbers for B2B campaigns.
• Contact sync & deduplication — validate imported address books before sync.

Accuracy

The validator returns a result within ~200 ms (p50) at our MEGA tier and dedicated endpoint. Because WhatsApp users can uninstall or deregister at any time, we recommend re-validating critical lookups immediately before acting on the result. Historical lookups are cached for 24 hours by default; you can override or disable the cache per-request.

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