Quote PDFs in Express

Why quotes become PDFs

A quote is an offer with an expiry, and it gets forwarded to people who will never log into your product. It has to stand alone and it has to be fixed at the moment it was sent. That is the difference between a document and a view of a database, and it is why sales teams keep asking for this.

What a quote has to carry

Before any of the code below matters, the template has to produce a document that is actually a quote. These are the fields that make it one, and the ones a reader or an auditor will look for first.

• a quote reference, which the eventual order will cite
• the validity date, after which the pricing no longer stands
• each line with the price offered, which may not be list price
• any discount shown as a discount rather than folded into the unit price
• the terms attached to the offer: payment schedule, lead time, exclusions

Turning your whichever view engine you configured, commonly EJS or Handlebars template into a document

You already have the markup. App.render("invoice", data, (err, html) => ...) gives you it as a string, which is the only input the render needs. app.render gives you the HTML string rather than writing it to a response, which is exactly what you want here. Note it is callback-based; promisify it once rather than nesting.

The Express implementation

fetch ships with the runtime, so this adds no dependency. The render happens in a route handler that pipes the response, and you pipe the upstream body into res.

// routes/quotes.js
import { pipeline } from "node:stream/promises";
import { Readable } from "node:stream";
import { promisify } from "node:util";

const renderView = promisify(app.render.bind(app));

app.get("/quotes/:id.pdf", async (req, res, next) => {
  try {
    const quote = await db.quotes.find(req.params.id);
    const html = await renderView("quote_pdf", { quote });

    const upstream = await fetch("https://api.pdfpipe.xyz/v1/pdf", {
      method: "POST",
      headers: {
        Authorization: `Bearer ${process.env.PDFPIPE_KEY}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        html,
        options: { format: "A4", printBackground: true },
      }),
    });

    if (!upstream.ok) throw new Error(`render failed: ${upstream.status}`);

    // Header first, then pipe. res.send would buffer the whole document.
    res.setHeader("Content-Type", "application/pdf");
    res.setHeader("Content-Disposition", `attachment; filename="quote-${req.params.id}.pdf"`);
    await pipeline(Readable.fromWeb(upstream.body), res);
  } catch (err) {
    next(err);
  }
});

The CSS that makes a quote page correctly

The layout problem specific to this document is that optional line items and discount blocks make the length unpredictable, so the signature area must not orphan onto a page of its own. These rules handle it.

/* Backgrounds are dropped unless printBackground is set on the
   request, which is the usual reason a document renders in plain
   black and white when it looked right in the browser. */
@page {
  size: A4;
  margin: 18mm 16mm;
}

table { break-inside: avoid; }
h2    { break-after: avoid; }

What goes wrong in Express

res.send on a Buffer sets Content-Length correctly but has already read the whole document into memory. res.end with no Content-Type makes the browser render the PDF bytes as text. Set the header, then pipe.

What people try first

Most Express projects reach for puppeteer, launched per request. That downloads roughly 300 MB of Chromium into your image and holds a browser process per concurrent render. That works until it is running on more than one machine, at which point the browser becomes the thing you operate rather than the thing you use.

Where the quote lives afterwards

Rendering is the short part. A quote is dead once it expires or converts, so retention is short and driven by the sales system rather than by law. What matters is that the version the customer received is the one you can produce later, because a disputed price is settled by the document that was sent.

Getting the document right

• Check the validity date, since a quote without one is an open-ended commitment.
• Generation is triggered by a salesperson sending it, so latency is felt directly by a person waiting, so size the timeout for that path rather than for a health check.
• These are produced one at a time by a person who is waiting, so latency is felt directly.
• Backgrounds are painted by default here, so a design that uses colour needs nothing set. Only an explicit print_background of false turns them off.

Frequently asked

Related

Other Express documents, and the same quote in other stacks.