Resend vs SendGrid vs Postmark vs Sendpository

import { Sendpository, SendpositoryError } from "sendpository";

const sendpository = new Sendpository(process.env.SENDPOSITORY_API_KEY);

try {
  const { id } = await sendpository.emails.send(
    {
      from: "Acme <billing@mail.yourdomain.com>",
      to: ["customer@example.com"],
      subject: "Your receipt",
      html: "<p>Thanks for your order.</p>",
      text: "Thanks for your order.",
      tags: { type: "receipt" },
    },
    // A retried job returns the first message's id instead of sending twice.
    { idempotencyKey: "receipt-10428" },
  );
  console.log(id);
} catch (err) {
  if (err instanceof SendpositoryError) console.error(err.type, err.message);
  throw err;
}

import { Resend } from "resend";

const resend = new Resend(process.env.RESEND_API_KEY);

const { data, error } = await resend.emails.send({
  from: "Acme <billing@yourdomain.com>",
  to: ["customer@example.com"],
  subject: "Your receipt",
  html: "<p>Thanks for your order.</p>",
  tags: [{ name: "type", value: "receipt" }],
});

await fetch("https://api.sendgrid.com/v3/mail/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.SENDGRID_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    personalizations: [{ to: [{ email: "customer@example.com" }] }],
    from: { email: "billing@yourdomain.com", name: "Acme" },
    subject: "Your receipt",
    content: [{ type: "text/html", value: "<p>Thanks for your order.</p>" }],
    categories: ["receipt"],
  }),
}); // 202, empty body

await fetch("https://api.postmarkapp.com/email", {
  method: "POST",
  headers: {
    "X-Postmark-Server-Token": process.env.POSTMARK_SERVER_TOKEN,
    "Content-Type": "application/json",
    Accept: "application/json",
  },
  body: JSON.stringify({
    From: "Acme <billing@yourdomain.com>",
    To: "customer@example.com",
    Subject: "Your receipt",
    HtmlBody: "<p>Thanks for your order.</p>",
    TextBody: "Thanks for your order.",
    Tag: "receipt",
    MessageStream: "outbound",
  }),
});