Generate invoice PDFs in Node.js

The simplest way to generate invoice PDFs in Node.js is to POST an invoice template and your billing JSON to the Docweave API with the built-in fetch — no headless browser to install, launch, or keep patched yourself.

An invoice template with placeholders

Write plain HTML with {{ placeholders }} for the number, customer, line items, subtotal, tax, total, and due date:

<article style="font-family: sans-serif; color: #111;">
  <header style="display:flex; justify-content:space-between;">
    <h1>Invoice {{ number }}</h1>
    <div>Due {{ due_date }}</div>
  </header>

  <p>Billed to: {{ customer }}</p>

  <table style="width:100%; border-collapse:collapse;">
    <thead>
      <tr>
        <th style="text-align:left; border-bottom:1px solid #ccc;">Item</th>
        <th style="text-align:right; border-bottom:1px solid #ccc;">Qty</th>
        <th style="text-align:right; border-bottom:1px solid #ccc;">Price</th>
      </tr>
    </thead>
    <tbody>
      {{{ line_items }}}
    </tbody>
  </table>

  <p style="text-align:right; margin-top:16px;">Subtotal: {{ subtotal }}</p>
  <p style="text-align:right;">Tax: {{ tax }}</p>
  <p style="text-align:right;"><strong>Total due: {{ total }}</strong></p>
</article>

Generate the invoice PDF from Node.js

Using only fetch and node:fs/promises (both built into modern Node.js), POST the template and data to /api/v1/pdf and write the raw response bytes to a file:

import { writeFile } from "node:fs/promises";

const template = `<article style="font-family: sans-serif; color: #111;">
  <header style="display:flex; justify-content:space-between;">
    <h1>Invoice {{ number }}</h1>
    <div>Due {{ due_date }}</div>
  </header>
  <p>Billed to: {{ customer }}</p>
  <table style="width:100%; border-collapse:collapse;">
    <thead>
      <tr>
        <th style="text-align:left; border-bottom:1px solid #ccc;">Item</th>
        <th style="text-align:right; border-bottom:1px solid #ccc;">Qty</th>
        <th style="text-align:right; border-bottom:1px solid #ccc;">Price</th>
      </tr>
    </thead>
    <tbody>{{{ line_items }}}</tbody>
  </table>
  <p style="text-align:right; margin-top:16px;">Subtotal: {{ subtotal }}</p>
  <p style="text-align:right;">Tax: {{ tax }}</p>
  <p style="text-align:right;"><strong>Total due: {{ total }}</strong></p>
</article>`;

const lineItemsHtml = [
  { name: "Consulting — Sprint 12", qty: 1, price: "$1,200.00" },
  { name: "Support retainer", qty: 1, price: "$300.00" },
]
  .map(
    (item) =>
      `<tr><td>${item.name}</td><td style="text-align:right;">${item.qty}</td><td style="text-align:right;">${item.price}</td></tr>`
  )
  .join("");

const response = await fetch("https://docweave.dev/api/v1/pdf", {
  method: "POST",
  headers: {
    Authorization: "Bearer dw_live_your_key",
    "Content-Type": "application/json",
    Accept: "application/pdf",
  },
  body: JSON.stringify({
    source: {
      type: "template",
      template,
      data: {
        number: "INV-042",
        customer: "Acme Inc.",
        due_date: "2026-08-01",
        line_items: lineItemsHtml,
        subtotal: "$1,500.00",
        tax: "$120.00",
        total: "$1,620.00",
      },
    },
    idempotencyKey: "inv-042",
  }),
});

if (!response.ok) {
  throw new Error(`Docweave API error: ${response.status} ${await response.text()}`);
}

const pdfBuffer = Buffer.from(await response.arrayBuffer());
await writeFile("invoice-042.pdf", pdfBuffer);

console.log("Saved invoice-042.pdf");

…or from an AI agent

The same invoice workflow works from an AI agent with no fetch code at all. Run npx @docweave/mcp and your agent gets a generate_pdf tool that wraps the same render orchestration as the REST endpoint:

// From an AI agent over MCP — no fetch/HTTP boilerplate:
// npx @docweave/mcp
generate_pdf({
  source: {
    type: "template",
    template: "<h1>Invoice {{ number }}</h1><p>Billed to {{ customer }}</p><p>Total due: {{ total }}</p>",
    data: { number: "INV-042", customer: "Acme Inc.", total: "$1,620.00" }
  },
  outputPath: "/tmp/invoice-042.pdf"
})

FAQ