EmailChecker + Mailchimp

// Higienização em lote: Mailchimp -> EmailChecker -> Mailchimp
import { createHash } from 'node:crypto';

const DC = 'us21'; // sufixo da sua API key do Mailchimp
const AUDIENCE = 'abc123';
const EC = 'https://app.emailchecker.email/api/v1';
const ecH = {
  Authorization: `Bearer ${process.env.EC_API_KEY}`,
  'Content-Type': 'application/json',
};
const mcH = {
  Authorization: `Basic ${Buffer.from(`anystring:${process.env.MC_API_KEY}`).toString('base64')}`,
  'Content-Type': 'application/json',
};
const hash = (email) => createHash('md5').update(email.toLowerCase()).digest('hex');
const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

// 1) puxa a audiência inteira
const emails = [];
for (let offset = 0; ; offset += 1000) {
  const url = `https://${DC}.api.mailchimp.com/3.0/lists/${AUDIENCE}/members?count=1000&offset=${offset}&fields=members.email_address`;
  const pagina = await fetch(url, { headers: mcH }).then((r) => r.json());
  if (!pagina.members || pagina.members.length === 0) break;
  emails.push(...pagina.members.map((m) => m.email_address));
}

// 2) um POST por lote (até 100.000 emails) — não existe chamada por contato
const criado = await fetch(`${EC}/batch`, {
  method: 'POST',
  headers: ecH,
  body: JSON.stringify({ emails, name: `mailchimp-${AUDIENCE}` }),
}).then((r) => r.json());

// 3) polling até completed
let lote;
do {
  await sleep(30_000);
  lote = await fetch(`${EC}/batch/${criado.data.id}`, { headers: ecH }).then((r) => r.json());
} while (lote.data.status === 'pending' || lote.data.status === 'processing');
if (lote.data.status !== 'completed') throw new Error(`lote ${lote.data.status}`);

// 4) marca o resultado e arquiva quem não existe mais
for (const e of lote.data.emails) {
  const url = `https://${DC}.api.mailchimp.com/3.0/lists/${AUDIENCE}/members/${hash(e.email)}`;
  await fetch(url, {
    method: 'PATCH',
    headers: mcH,
    body: JSON.stringify({ merge_fields: { EMAIL_STATUS: e.result } }),
  });
  if (e.result === 'undeliverable') {
    await fetch(url, { method: 'DELETE', headers: mcH }); // arquiva, não apaga
  }
}