Block disposable email in Clerk

The code

// app/api/webhooks/clerk/route.ts
import { Webhook } from "svix";
import { headers } from "next/headers";
import { NextResponse } from "next/server";

const PIISEND_URL = "https://api.piisend.com/api/v1/intelligence/email";

export async function POST(req: Request) {
  const payload = await req.text();
  const wh = new Webhook(process.env.CLERK_WEBHOOK_SECRET!);
  const evt = wh.verify(payload, Object.fromEntries(await headers())) as any;

  if (evt.type === "user.created" && evt.data.email_addresses?.[0]?.email_address) {
    const email = evt.data.email_addresses[0].email_address;
    const r = await fetch(PIISEND_URL, {
      method: "POST",
      headers: {
        Authorization: `Bearer ${process.env.PIISEND_API_KEY!}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ email }),
    });
    if (r.ok && (await r.json()).signals?.disposable) {
      // Delete user or flag — prefer blocking before create when possible
      await fetch(`https://api.clerk.com/v1/users/${evt.data.id}`, {
        method: "DELETE",
        headers: { Authorization: `Bearer ${process.env.CLERK_SECRET_KEY!}` },
      });
    }
  }

  return NextResponse.json({ ok: true });
}