Email from a Replit app, with the key in Secrets.

import os
from notix import Notix

notix = Notix(os.environ["NOTIX_API_KEY"])

resp, _ = notix.emails.send(payload={
    "from": "Acme <hello@acme.com>",
    "to": "maria@example.com",
    "subject": "Welcome to Acme",
    "html": "<p>Glad you are here.</p>",
})
print(resp["emailId"])

import { Notix } from "notix-js";

const notix = new Notix(process.env.NOTIX_API_KEY!);

export async function POST(request: Request) {
  const { to } = await request.json();
  const { data, error } = await notix.emails.send({
    from: "Acme <hello@acme.com>",
    to,
    subject: "Welcome to Acme",
    html: "<p>Glad you are here.</p>",
  });
  if (error) return Response.json({ error }, { status: 502 });
  return Response.json({ id: data?.emailId });
}