Use the capabilities endpoint to decide which protocol to use.

​
Check capabilities

curl -H 'Authorization: Bearer YOUR_API_KEY' \
  'https://backend.blooio.com/v1/api/contacts/%2B15551234567/capabilities'
Response example: 
{
  "contact": "+15551234567",
  "type": "phone",
  "capabilities": { "imessage": true, "sms": true },
  "lastChecked": "2024-01-01T00:00:00.000Z"
}

​
Send on the best channel

If imessage is true, prefer iMessage; otherwise send SMS. 
import fetch from 'node-fetch'

async function sendBest(contact, text) {
  const capsRes = await fetch(`https://backend.blooio.com/v1/api/contacts/${encodeURIComponent(contact)}/capabilities`, {
    headers: { 'Authorization': `Bearer ${process.env.BLOOIO_API_KEY}` }
  })
  const caps = await capsRes.json()
  const protocol = caps.capabilities?.imessage ? 'imessage' : 'sms'

  return fetch('https://backend.blooio.com/v1/api/messages', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${process.env.BLOOIO_API_KEY}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ to: contact, text, metadata: { protocol } })
  })
}
Store the chosen protocol in metadata for downstream analytics.