Enviar WhatsApp con Node.js: ejemplo de API REST con fetch

cURL

curl -X POST https://api.zapzapapi.com/api/v1/SEU_INSTANCE_ID/send/text \
  -H "Content-Type: application/json" \
  -H "x-api-key: SUA_API_KEY" \
  -H "x-api-secret: SEU_API_SECRET" \
  -d '{"number":"5511999999999","text":"Olá! Teste de envio pela API."}'

Node.js

const BASE = "https://api.zapzapapi.com/api/v1/" + process.env.ZAPZAP_INSTANCE_ID;
const HEADERS = {
  "Content-Type": "application/json",
  "x-api-key": process.env.ZAPZAP_API_KEY,
  "x-api-secret": process.env.ZAPZAP_API_SECRET,
};

export async function enviarTexto(number, text) {
  const r = await fetch(BASE + "/send/text", {
    method: "POST",
    headers: HEADERS,
    body: JSON.stringify({ number, text }),
    signal: AbortSignal.timeout(15000),
  });
  const corpo = await r.json().catch(() => ({}));
  if (!r.ok) throw Object.assign(new Error("ZapZap " + r.status), { status: r.status, corpo });
  return corpo; // { messageId, status }
}

console.log(await enviarTexto("5511999999999", "Olá! Seu pedido saiu para entrega."));

Node.js

export async function enviarPdf(number, file, docName, text = "") {
  const r = await fetch(BASE + "/send/media", {
    method: "POST",
    headers: HEADERS,
    body: JSON.stringify({ number, type: "document", file, docName, text }),
    signal: AbortSignal.timeout(60000),
  });
  if (!r.ok) throw new Error("ZapZap " + r.status + " " + (await r.text()));
  return r.json();
}

Node.js

const dormir = (ms) => new Promise((ok) => setTimeout(ok, ms));

export async function enviarComRetry(number, text, tentativas = 4) {
  for (let i = 0; i < tentativas; i++) {
    try {
      return await enviarTexto(number, text);
    } catch (e) {
      const transitorio = !e.status || e.status === 429 || e.status >= 500;
      if (!transitorio || i === tentativas - 1) throw e;
      await dormir(2 ** i * 1000 + Math.random() * 500);
    }
  }
}

export async function enviarLista(contatos) {
  for (const [numero, texto] of Object.entries(contatos)) {
    await enviarComRetry(numero, texto);
    await dormir(2000 + Math.random() * 4000);
  }
}

Node.js (Express)

import express from "express";

const app = express();
app.use(express.json({ limit: "2mb" }));

app.post("/webhooks/zapzap", (req, res) => {
  res.sendStatus(200); // confirma primeiro
  const evento = req.body;
  const msg = evento.data && evento.data.message;
  if (evento.event !== "messages" || !msg || msg.fromMe) return;
  console.log("mensagem de", msg.chatid, ":", msg.text);
});

app.listen(3000);