Check Whether a Number Is on WhatsApp
View all WhatsApp Messaging API endpoints →Check whether a given phone number has an active WhatsApp account, using a connected session. Pass the full international number (digits only, no +) in the path. Returns whether the number exists along with its JID. Use it to validate recipients before sending to improve deliverability and reduce wasted sends.
API Features
Recipient validation Confirm a number is on WhatsApp before you attempt to message it
Session-based check Uses your connected session so results reflect a live WhatsApp query
Returns the JID Provides the resolved JID alongside the exists flag for follow-up calls
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GET
/api/project/whatsapp-messaging/check-contact-exists API Response (JSON)
{} curl -X GET 'https://api.opendata-api.com/api/project/whatsapp-messaging/check-contact-exists?key=<API_KEY>&sessionId=<sessionId>&phoneNumber=<phoneNumber>'
curl -X GET 'https://api.opendata-api.com/api/project/whatsapp-messaging/check-contact-exists?key=<API_KEY>&sessionId=<sessionId>&phoneNumber=<phoneNumber>'
Query Result
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Use Cases
- Pre-send validation to avoid messaging non-WhatsApp numbers
- List hygiene: flag inactive or invalid numbers in a contact list
- Signup flows: confirm WhatsApp availability before choosing it as a channel