Generate an Invoice PDF From JSON in Node.js (No Templates, No Puppeteer Setup)

Stanley Ismaillar — Mon, 19 Oct 2026 00:53:10 +0000

Every app that charges money eventually needs to send an invoice. The usual path is: pick a PDF library, design a layout, fight with page breaks, then maintain it forever.

This post shows a shorter route: describe the invoice as JSON, get a PDF back. I'll use GetInvoicePDF, a small API I built, but I'll also be upfront about when you should not use it.

1. Get an API key

2. Send the invoice data

// generate-invoice.mjs  (Node 18+, no dependencies)
import { writeFile } from "node:fs/promises";

const res = await fetch("https://getinvoicepdf.dev/api/v1/invoices", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.GETINVOICEPDF_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    template: "modern",
    invoiceNumber: "INV-1001",
    date: "2026-10-16",
    currency: "USD",
    accentColor: "#0f766e",
    seller: { name: "Acme Studio", email: "billing@acme.example", address: "12 Market St, Austin, TX" },
    buyer: { name: "Jane Client", email: "jane@client.example" },
    lineItems: [
      { description: "Website design", quantity: 1, unitPrice: 1800 },
      { description: "Revisions (hours)", quantity: 4, unitPrice: 95 },
    ],
    taxRate: 8.25,
    notes: "Payment due within 14 days. Thank you!",
  }),
});

if (!res.ok) throw new Error(`${res.status}: ${await res.text()}`);
await writeFile("invoice.pdf", Buffer.from(await res.arrayBuffer()));
console.log("saved invoice.pdf");

GETINVOICEPDF_KEY=your_key node generate-invoice.mjs

That's the whole integration. The totals, tax line and layout are computed for you.

3. Store the invoice and fetch it later

Add ?format=url and the API keeps the PDF and returns an id and a url instead of the file:

const res = await fetch("https://getinvoicepdf.dev/api/v1/invoices?format=url", { /* same options */ });
const { id, url } = await res.json();

That URL is private: it only works with the same API key (or when you're signed in to the dashboard), so it isn't a link you can paste into an email to a customer. To get the PDF back later, request it with your key:

const pdf = await fetch(url, { headers: { Authorization: `Bearer ${process.env.GETINVOICEPDF_KEY}` } });

To send an invoice to a customer, attach the PDF from step 2 to your own email.

4. Turn an invoice into a receipt

When the customer pays, send the same data with paid: true (and optionally paidDate and paymentMethod). The document gets a PAID stamp and becomes a receipt.

Python

import os, requests

r = requests.post(
    "https://getinvoicepdf.dev/api/v1/invoices",
    headers={"Authorization": f"Bearer {os.environ['GETINVOICEPDF_KEY']}"},
    json={
        "seller": {"name": "Acme Studio"},
        "buyer": {"name": "Jane Client"},
        "lineItems": [{"description": "Consulting", "quantity": 3, "unitPrice": 150}],
        "taxRate": 0,
    },
)
r.raise_for_status()
open("invoice.pdf", "wb").write(r.content)

When not to use this

You need pixel-perfect control of a custom layout: use an HTML-to-PDF service or run Puppeteer yourself.
You need legally structured e-invoices (Factur-X, ZUGFeRD, PEPPOL, FatturaPA): this produces a normal PDF, not those formats. If that's your market, I'd like to hear about it, since I'd expect it to be the biggest gap.

Under the hood (for the curious)

A Next.js app renders the chosen template to HTML and Puppeteer prints it to PDF. API keys are stored as SHA-256 hashes. It runs on Fly.io with Postgres.

Questions, bugs, or a field you need that's missing? Leave a comment, I read all of them.

DEV Community: Stanley Ismaillar