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GET
/
{instance}
/
contacts
/
check-exists
Check if contact exists on WhatsApp
curl --request GET \
  --url https://app.hypersender.com/api/whatsapp/v1/{instance}/contacts/check-exists \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "phone": "201553730661"
}
'
{ "numberExists": true, "chatId": "[email protected]" }

Documentation Index

Fetch the complete documentation index at: https://docs.hypersender.com/llms.txt

Use this file to discover all available pages before exploring further.

Check if a phone number is registered on WhatsApp before attempting to send messages. This endpoint allows you to:
  • Verify if a phone number exists on WhatsApp
  • Get the correct chatId format for messaging
  • Prevent errors when sending messages to non-existent numbers
This is useful for validating contacts before sending messaging operations or when integrating with external systems.

​
Use Cases

​
Contact Validation

Before sending messages to a list of contacts, verify which numbers are actually registered on WhatsApp.

​
CRM Integration

When syncing contacts from your CRM, check their WhatsApp availability to enable messaging features.

​
User Onboarding

Verify if a user’s phone number is on WhatsApp during registration or account setup.
This endpoint is very useful to avoid getting blocked by WhatsApp, As it prevent you from sending messages to non-existing numbers.

​
Response Examples

​
Existing Contact

When the phone number is registered on WhatsApp: 
{
  "numberExists": true,
  "chatId": "[email protected]"
}

​
Non-existing Contact

When the phone number is not registered on WhatsApp: 
{
  "numberExists": false,
  "chatId": null
}
The chatId can be in any format +20123456789, 20123456789, 0123456789, or 123456789

Authorizations

​
Authorization
string
header
required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

​
Accept
string

application/json

Example:

"application/json"

​
Content-Type
string

application/json

Example:

"application/json"

Path Parameters

​
instance
string
required

Instance UUID copied from hypersender dashboard

Example:

"{{ instance_id }}"

Body

application/json
​
phone
string
required

Phone number to check (with country code, without + or spaces)

Example:

"201553730661"

Response

Successful response

​
numberExists
boolean

Whether the phone number exists on WhatsApp

​
chatId
string | null

The WhatsApp chat ID if number exists, null otherwise