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": 1755815097884,
  "api_version": "v2025.8.21",
  "object": "response",
  "data": {
    "message_id": "wapp_1234567890"
  }
}