HK 
Haraka
High-performance, pluggable open-source SMTP server (Node.js).
High-performance, pluggable open-source SMTP server (Node.js).
MailKite's own inbound MX edge runs on Haraka — so you get Haraka-grade handling without running it.
A minimal, copy-paste starter. Swap in your own domain and API key.
import { verifyWebhook } from "@mailkite/client";
// MailKite POSTs every inbound email at your domain as JSON.
// Point a route at this handler in the MailKite dashboard.
export default async function handler(req: Request) {
const raw = await req.text();
const sig = req.headers.get("x-mailkite-signature") ?? "";
// Reject anything not signed by your webhook secret
const ok = await verifyWebhook(sig, raw, process.env.MK_WEBHOOK_SECRET!);
if (!ok) return new Response("bad signature", { status: 401 });
const email = JSON.parse(raw);
// Route into Haraka: open a ticket, create a task, store a record
await routeIntoName(email); // email.from · email.subject · email.text
return new Response(JSON.stringify({ ok: true }));
}Haraka is a high-performance, pluggable SMTP server written in Node.js, widely used as the inbound MX edge for custom mail platforms and high-volume senders. Its plugin architecture lets you intercept every stage of the SMTP transaction. It's infrastructure for teams building their own mail handling, not an end-user product.
Open source (self-host)
As a pluggable SMTP daemon — most often the inbound MX edge of a custom mail platform, where its plugins handle spam filtering, routing, and handoff.
Yes — MailKite's inbound MX edge is a Haraka instance that parses and authenticates mail before POSTing it as JSON to your webhook.
Point a domain, drop in a webhook URL, and send your first email in minutes. Unlimited domains, no credit card.
