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POST
Check numbers on WhatsApp
Ask which numbers are reachable on WhatsApp before you send to them. Nothing is sent to anybody.

Notes

  • 1 to 50 numbers per request. More returns 400 invalid_request with details.max_numbers.
  • Duplicates are removed before the lookup. submitted is what you sent, checked is how many distinct numbers were actually looked up.
  • Results come back in the order you submitted them.
  • This uses one of your connected numbers to do the lookup, so instance_id is required and that number must be connected — otherwise you get 409 instance_not_connected.
  • A check is not a message. It does not appear in your usage figures and does not consume a trial allowance. It does count against your per-minute rate limit.

Reading the results

boolean | null
true — on WhatsApp. false — not on WhatsApp. null — the check could not be completed for that number.
null does not mean “not on WhatsApp”. Treat it as “unknown” and retry later, or send anyway. Collapsing null into false will make you skip real customers.
string | null
The number WhatsApp actually answers on. In some countries this differs from the number you dialled — Brazil’s extra 9th digit is the classic case. When it differs, send to this number, not the one you looked up.

Example

Working through a large list quickly still puts your number at risk, whatever the batch size. Read Checking numbers before you send for how to pace it.

Authorizations

apikey
string
header
required

Your API key, sent in an apikey request header. Never in the URL, never as a Bearer token.

Body

application/json
instance_id
string<uuid>
required

Which of your connected numbers to send FROM. Copy it from your numbers screen in the portal, or from GET /v1/instances. It must belong to your account.

Example:

"3f9c1a2b-7d4e-4c81-9f0a-2b6d5e8c1a34"

numbers
string[]
required

1 to 50 numbers per request, each with its country code. Duplicates are removed before the lookup.

Required array length: 1 - 50 elements
Example:

Response

Lookup complete.

success
boolean
data
object
request_id
string<uuid>