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POST
/
whatsapp
cURL
curl --request POST \
  --url https://api.contiguity.com/send/whatsapp \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "to": "+1234567890",
  "message": "Hello, world!"
}'
{
  "id": "req_xxxxxxxxxxxxxxxx",
  "timestamp": 1757916599341,
  "api_version": "v2025.9.15",
  "object": "response",
  "data": {
    "message_id": "wapp_1234567890"
  }
}
Only customers who lease numbers that support WhatsApp can use this endpoint.
Phone numbers must be in E.164 format with country codes.

Authorizations

​
Authorization
string
header
required

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

Body

application/json
​
to
string
required

Recipient's WhatsApp number. Must be in E.164 format.

Example:

"+1234567890"

​
message
string
required

The WhatsApp message to send

Example:

"Hello, world!"

​
from
string

Your leased WhatsApp number. If none is provided, we will use a random WhatsApp number of yours.

Example:

"+15555555555"

​
fallback
object

Should Contiguity fallback to SMS/RCS if the recipient does not have WhatsApp, or if WhatsApp fails to send?

Example:
{
  "when": ["whatsapp_unsupported", "whatsapp_fails"],
  "from": "+15555555555"
}
​
attachments
string[]

Attachments to send. Can be a URL to your attachment (e.g. example.com/image.png) or a base64 string. Max 10 attachments, with a cumulative size of 50MB.

Example:
[
  "https://example.com/image.png",
  "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAYCAYAAADgdz34AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAPUlEQVR4nGNgYGBgAAABAAABATDeu7sAAAAASUVORK5CYII="
]

Response

Send a WhatsApp message

​
id
string
required
Example:

"req_xxxxxxxxxxxxxxxx"

​
timestamp
number
required
Example:

1757916599341

​
api_version
string
required
Example:

"v2025.9.15"

​
object
string
required
Example:

"response"

​
data
object
required
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