import Inbound from 'inboundemail';

const client = new Inbound({
  apiKey: process.env['INBOUND_API_KEY'], // This is the default and can be omitted
});

const response = await client.emails.send({ from: 'from', subject: 'subject', to: 'string' });

console.log(response.id);

{
  "id": "<string>",
  "message_id": "<string>",
  "scheduled_at": "<string>",
  "status": "sent",
  "timezone": "<string>"
}