Quickstart: Next.js

npm install @email-fast/nodejs

# .env.local
EMAILFAST_API_KEY=ef_sandbox_...   # swap to ef_live_… at launch

// app/api/welcome/route.ts
import { EmailFast } from "@email-fast/nodejs";
import { NextResponse } from "next/server";

const ef = new EmailFast({ apiKey: process.env.EMAILFAST_API_KEY!, baseUrl: "https://api.emailfast.dev" });

export async function POST(req: Request) {
  const { email, name } = await req.json();

  const { id } = await ef.send({
    to: email,
    subject: "Welcome!",
    html: "<h1>Hi {{name}}</h1>",
    data: { name },
    idempotency_key: `welcome-${email}`, // a double-submit can't double-send
  });

  return NextResponse.json({ id });
}

// app/actions.ts
"use server";
import { EmailFast } from "@email-fast/nodejs";

const ef = new EmailFast({ apiKey: process.env.EMAILFAST_API_KEY!, baseUrl: "https://api.emailfast.dev" });

export async function sendWelcome(formData: FormData) {
  await ef.send({
    to: String(formData.get("email")),
    subject: "Welcome!",
    html: "<p>You're in.</p>",
  });
}