Send Email with Next.js

Installation

npm install reloop-email

Setup environment variables

Add your Reloop API key to .env.local (server-only — do not use NEXT_PUBLIC_):

RELOOP_API_KEY=rl_your_api_key_here

Shared client

// lib/reloop.ts
import { Reloop } from "reloop-email";

export const reloop = new Reloop({
  apiKey: process.env.RELOOP_API_KEY!,
});

Route Handler

// app/api/send-email/route.ts
import { NextResponse } from "next/server";
import { reloop } from "@/lib/reloop";

export async function POST(request: Request) {
  try {
    const { to, subject, html, text } = await request.json();

    const { response, emailError } = await reloop.mail.send({
      from: "Acme <onboarding@mail.yourdomain.com>",
      to,
      subject: subject ?? "Hello from Next.js",
      html: html ?? "<p>Congrats on sending your first email via Reloop!</p>",
      text: text ?? "Congrats on sending your first email via Reloop!",
    });

    if (emailError) {
      return NextResponse.json({ error: emailError }, { status: 502 });
    }

    return NextResponse.json(response);
  } catch (error) {
    return NextResponse.json({ error }, { status: 500 });
  }
}

Server Action

// app/actions/send-email.ts
"use server";

import { reloop } from "@/lib/reloop";

export async function sendWelcomeEmail(email: string) {
  const { response, emailError } = await reloop.mail.send({
    from: "Acme <onboarding@mail.yourdomain.com>",
    to: email,
    subject: "Welcome",
    html: "<p>Thanks for signing up.</p>",
    text: "Thanks for signing up.",
  });

  if (emailError) {
    return { ok: false as const, error: "Failed to send" };
  }

  return { ok: true as const, messageId: response?.messageId };
}

Full guide

For forms, auth, Edge runtime, Vercel deploy, and a full comparison of Server Actions vs Route Handlers, see the blog post: How to Send Email in Next.js App Router.