Send and receive email in Next.js

// app/api/contact/route.ts
export async function POST(req: Request) {
  const { name, email, message } = await req.json();

  const res = await fetch("https://api.usemektup.com/v1/emails", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.MEKTUP_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      from: "website@yourapp.com",
      to: "hello@yourapp.com",
      replyTo: email,
      subject: `Message from ${name}`,
      text: message,
    }),
  });

  return Response.json(await res.json(), { status: res.status });
}

// app/api/inbound/route.ts
import crypto from "node:crypto";

export async function POST(req: Request) {
  const raw = await req.text(); // the exact body Mektup signed
  const expected = crypto.createHmac("sha256", process.env.MEKTUP_WEBHOOK_SECRET!)
    .update(raw).digest("hex");
  const got = (req.headers.get("x-mektup-signature") ?? "").replace("sha256=", "");
  if (got.length !== expected.length ||
      !crypto.timingSafeEqual(Buffer.from(got), Buffer.from(expected))) {
    return new Response("bad signature", { status: 401 });
  }

  const { mailbox, message } = JSON.parse(raw);
  await saveTicket(mailbox, message); // your code
  return new Response(null, { status: 200 });
}