WhatsApp Number Lookup API: Validate & Enrich Phone Numbers

Published August 23, 2026

A WhatsApp number lookup API lets you turn a raw phone number into useful, structured data: Is this number on WhatsApp? What’s its public profile — avatar, “about” text, business info, last-seen? Instead of maintaining fragile automations around the WhatsApp apps, you call one HTTP endpoint and get JSON back.

This guide walks through what the WhatsApp Number Validation & Profile Lookup API can do and how to start using it.

What the API can do

The project groups several operations around one goal — learning about a number:

  • Check registration (check-exist-by-phone, check-exist-by-cc-phone) — is the number linked to an active WhatsApp account?
  • Profile data (get-avatar, get-about) — display photo and status/about text.
  • Presence (get-presence, check-active) — online status / last-seen signals.
  • Business profile (get-biz-profile) — details for WhatsApp Business accounts.
  • Bulk validation (batch-check-10) — check up to 10 numbers in one request.

Step 1 — Get an API key

Sign up, then open your Dashboard and copy an active API key. New accounts get free credits, so you can experiment immediately.

Step 2 — Validate a number

Pass the full number in international format (digits only):

curl "https://api.opendata-api.com/api/project/whatsapp/check-exist-by-phone?key=YOUR_API_KEY&phoneNumber=15551234567"

For registered numbers, the check returns an identifier (userHash) you can feed into the profile operations.

Step 3 — Enrich with profile data

Use the userHash from the previous step to pull public profile fields:

curl "https://api.opendata-api.com/api/project/whatsapp/get-avatar?key=YOUR_API_KEY&userHash=USER_HASH"
curl "https://api.opendata-api.com/api/project/whatsapp/get-about?key=YOUR_API_KEY&userHash=USER_HASH"

This two-step design keeps the cheap registration check separate from the richer (and credit-heavier) profile lookups, so you only pay for enrichment on numbers that are actually registered.

Where it’s used

  • Lead qualification — verify and enrich inbound leads before routing to sales.
  • List hygiene — keep CRM contacts limited to WhatsApp-reachable numbers.
  • Onboarding — confirm a user can receive WhatsApp messages before switching channels.
  • Research & enrichment — attach public profile data to known numbers at scale.

Best practices

  • Validate before you enrich — skip profile calls for numbers that fail the registration check.
  • Normalize numbers to E.164 digits (country code, no + or punctuation).
  • Cache userHash results so repeat lookups don’t cost extra credits.
  • Stay compliant — only process numbers you have a lawful basis to use, and respect WhatsApp’s terms.

Get started

Try it in the browser on the WhatsApp Number Validation page, read the check-exist-by-phone reference, and review pricing when you’re ready to scale beyond the free credits.