HTML to PDF in Node.js — without bundling a browser

const API_KEY = process.env.HTML2DOCHUB_API_KEY!;

export async function renderPdf(html: string): Promise<Buffer> {
  const res = await fetch("https://api.html2dochub.com/v1/render", {
    method: "POST",
    headers: { "X-API-Key": API_KEY, "Content-Type": "application/json" },
    body: JSON.stringify({
      type: "pdf",
      html,
      options: { format: "A4", margin: "18mm" },
    }),
  });
  if (!res.ok) throw new Error(`Render failed: ${res.status}`);
  const job = await res.json();

  const pdfRes = await fetch(job.download_url);
  return Buffer.from(await pdfRes.arrayBuffer());
}

// app/api/invoice/[id]/pdf/route.ts
import { NextRequest, NextResponse } from "next/server";

export async function GET(
  _req: NextRequest,
  { params }: { params: { id: string } },
) {
  const invoice = await getInvoice(params.id);
  const html = renderInvoiceTemplate(invoice);

  const res = await fetch("https://api.html2dochub.com/v1/render", {
    method: "POST",
    headers: {
      "X-API-Key": process.env.HTML2DOCHUB_API_KEY!,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ type: "pdf", html, options: { format: "A4" } }),
  });
  const job = await res.json();
  const pdf = await fetch(job.download_url).then((r) => r.arrayBuffer());

  return new NextResponse(pdf, {
    headers: {
      "Content-Type": "application/pdf",
      "Content-Disposition": `attachment; filename="invoice-${params.id}.pdf"`,
    },
  });
}

const express = require("express");
const app = express();

app.get("/invoice/:id.pdf", async (req, res) => {
  const invoice = await Invoice.findById(req.params.id);
  const html = renderTemplate("invoice", { invoice });

  const apiRes = await fetch("https://api.html2dochub.com/v1/render", {
    method: "POST",
    headers: {
      "X-API-Key": process.env.HTML2DOCHUB_API_KEY,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ type: "pdf", html, options: { format: "A4" } }),
  });
  const job = await apiRes.json();

  const pdfRes = await fetch(job.download_url);
  res.set("Content-Type", "application/pdf");
  res.set("Content-Disposition", `attachment; filename="invoice-${req.params.id}.pdf"`);
  pdfRes.body.pipe(res);
});

app.listen(3000);

import { Worker, Queue } from "bullmq";

export const reportQueue = new Queue("reports");

new Worker("reports", async (job) => {
  const { reportId, userId } = job.data;
  const idempotencyKey = `report:${reportId}:v${job.attemptsMade}`;

  const res = await fetch("https://api.html2dochub.com/v1/render", {
    method: "POST",
    headers: {
      "X-API-Key": process.env.HTML2DOCHUB_API_KEY!,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      type: "pdf",
      mode: "async",
      html: await buildReportHtml(reportId),
      webhook_url: `${process.env.BASE_URL}/webhooks/pdf-ready`,
      tag: `user:${userId}`,
      idempotency_key: idempotencyKey,
    }),
  });
  if (!res.ok) throw new Error(`Render enqueue failed: ${res.status}`);

  const { id: html2DochubJobId } = await res.json();
  await db.report.update({ where: { id: reportId }, data: { html2DochubJobId } });
}, { concurrency: 4 });