Kubernetes + MailKite

Kubernetes doesn't send email natively, but you can route inbound email to your cluster via MailKite webhooks. Use an Ingress-nginx annotation or a bare webhook endpoint to receive parsed email as clean JSON at any pod or service.

What you need

• A verified domain with SPF + DKIM published
• Your API key (mk_live_…)
• A Kubernetes cluster with an Ingress controller or a publicly reachable service

How it works

MailKite POSTs inbound email to your webhook URL. Your cluster processes it — create a ConfigMap, trigger a Job, or POST to an internal service. The handler runs inside your cluster, so it has direct access to Kubernetes APIs and internal networking.

Set up the webhook

Deploy a lightweight webhook receiver as a container in your cluster. This example listens on port 3000 and logs inbound email — extend it to call the Kubernetes API, update a ConfigMap, or trigger a CronJob.

// k8s-webhook.js — deploy as a container
const http = require('http');

const server = http.createServer((req, res) => {
  if (req.method !== 'POST') { res.writeHead(405); return res.end(); }
  let body = '';
  req.on('data', c => body += c);
  req.on('end', () => {
    const email = JSON.parse(body);
    console.log(`Inbound: ${email.from} → ${email.to} — ${email.subject}`);
    // Process: create a pod, update a ConfigMap, or call an internal API
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end('{"ok":true}');
  });
});
server.listen(3000);

Receive inbound email

Configure your MailKite domain's webhook URL to point at your Kubernetes endpoint. Every inbound email delivers this payload:

• from — sender address
• to — recipient address
• subject — email subject
• text — plain text body
• html — HTML body
• attachments — array of file objects

Test it

curl -X POST https://your-cluster.example.com/webhook/mailkite \
  -H "Content-Type: application/json" \
  -d '{"from":"test@example.com","to":"k8s@yourdomain.com","subject":"Hello from MailKite","text":"Test"}'

Troubleshooting

• Ensure your Ingress or LoadBalancer exposes the webhook endpoint publicly — MailKite must reach it from the internet.
• Use Cloudflare Tunnel or ngrok if your cluster is behind a firewall or private network.
• Check pod logs with kubectl logs -l app=webhook to verify inbound requests arrive.

See the SMTP relay docs for connection details, or Inbound webhooks for the full payload.