PDF generation in Node.js

Minimal example

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

const res = await fetch("https://papertype.dev/v1/pdf", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.PAPERTYPE_KEY}`, "Content-Type": "application/json" },
  body: JSON.stringify({ markdown: "# Weekly report\n\n## Summary\n\nAll systems nominal.", theme: "report", cover: true, toc: true }),
});
if (!res.ok) throw new Error(`${res.status}: ${(await res.json()).detail}`);
await writeFile("weekly-report.pdf", Buffer.from(await res.arrayBuffer()));
console.log(res.headers.get("X-Pages"), "pages;", res.headers.get("X-Quota-Used"), "of", res.headers.get("X-Quota-Limit"), "used");

Works with the built-in fetch in Node 18 and later. No package to install.

HTML from your template engine

Render the template to a string and post it with theme: "none" and your print CSS. Inline images as data: URIs.

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

const logo = `data:image/png;base64,${(await readFile("logo.png")).toString("base64")}`;
const html = renderInvoice({ invoice, logo });   // your template function
const css = await readFile("print.css", "utf8");
const res = await fetch("https://papertype.dev/v1/pdf", {
  method: "POST", headers,
  body: JSON.stringify({ html, css, theme: "none", page_size: "Letter", filename: `${invoice.number}.pdf` }),
});

Sending the PDF to a browser

In an HTTP handler, forward the bytes with the right headers. Keep the API key on the server; never expose it to the client.

res.setHeader("Content-Type", "application/pdf");
res.setHeader("Content-Disposition", 'attachment; filename="report.pdf"');
res.end(Buffer.from(await upstream.arrayBuffer()));

Errors and quotas

• 422: cannot render; the detail field says why. Fix the input rather than retrying.
• 429: monthly quota reached; queue the job. Plans are hard-capped, so there are no surprise charges.
• 413: source over 2 MB. 401: bad key.
• Concurrency: 2 renders at a time per account. Use a small queue (for example a promise pool of 2) for batch jobs.

Limits and pricing

• No JavaScript is executed. Send the final HTML; anything a script would have drawn or filled in will not appear.
• The renderer has no network access. Images, fonts and stylesheets at external URLs are never fetched; inline them as data: URIs. A request that references an external URL fails with a 422 that names the URL, rather than silently dropping the asset.
• Free-plan output carries a small papertype.dev footer mark. Paid plans (from $9/month) do not.

Plans are capped. When a plan's monthly document count is reached the API returns 429 until you upgrade or the month rolls over; there is no overage billing.

• Free: 50 documents/month, footer mark on output, no card required.
• Starter: $9/month, 500 documents, no mark.
• Pro: $29/month, 3,000 documents.
• Scale: $79/month, 15,000 documents.

Every response includes X-Quota-Used and X-Quota-Limit headers so you can watch usage without polling. Details on the pricing page.

Related

• PDF generation in Python
• HTML to PDF API
• Markdown to PDF API
• Generate invoice PDFs from JSON