Integration recipe

Print Shopify orders without anyone opening a browser.

Subscribe to an order webhook, build the packing slip or fetch the label, and send it to the printer at the bench that will pack it. About twenty lines in a function you already have.

Start printing Read the API docs

The recipe

Webhook in, paper out.

Shopify already tells you when an order is paid or a fulfillment is created. That is your trigger.

Subscribe to the webhook

orders/paid for pick-and-pack, or fulfillments/create if you print at the point of fulfillment. Point it at your own endpoint.

topic: orders/paid

Build the document

Render your packing slip as a PDF, or take your carrier's ZPL if you are printing a shipping label. Base64-encode either one.

contentType: pdf_base64

Send it to the right bench

Map the order's location to a printer ID you store, and send the job with an idempotency key built from the order ID.

POST /v1/print-jobs

webhooks/orders-paid.ts

const RocketPrint = require("rocketprint");

const rocketprint = new RocketPrint(process.env.ROCKETPRINT_KEY);

// Your own mapping — Shopify location ID → RocketPrint printer ID.
const SLIP_PRINTER = {
  "gid://shopify/Location/1234": "6a4738f7462183c7f5d70598",
};

export async function onOrderPaid(order) {
  const pdf = await renderPackingSlip(order);          // your existing renderer

  await rocketprint.printJobs.create({
    printerId: SLIP_PRINTER[order.location_id],
    title: `Packing slip ${order.name}`,
    contentType: "pdf_base64",
    content: pdf.toString("base64"),
    source: "shopify",
  }, {
    // Shopify re-delivers webhooks; this makes that harmless.
    idempotencyKey: `shopify-order-${order.id}-slip`,
  });
}

Practical notes

Things worth knowing first.

Packing slips as PDFs, labels as ZPL

A packing slip through that computer's driver is fine. A shipping label is not — ask your carrier for ZPL and send it as raw_base64 so the printer draws the barcode itself instead of it being redrawn on the way.

Shopify retries webhooks

That is a feature, and idempotency keys make it a harmless one. Build the key from the order or fulfillment ID and a repeated delivery returns the original job.

Multi-location stores

Keep your own map from Shopify location to printer ID. Adding a warehouse becomes a new row plus one app install, not a code change.

A sleeping bench computer is fine

If that computer is offline when the webhook fires, the job waits and prints when it reconnects. Your webhook handler still returns 200 immediately. How queueing works →

Questions

Shopify-specific questions.

Is this a Shopify app I install?

No. This is a recipe for your own backend or serverless function. You subscribe to a Shopify webhook, build the document, and send it to RocketPrint. Nothing is installed into your storefront.

Where does the label come from?

From whichever carrier or shipping platform you already buy postage through. Shopify tells you an order is ready; your carrier gives you the label; RocketPrint puts it on paper.

Can different locations print to different printers?

Yes. Map the Shopify location on the order to a printer ID you store yourself. Where it prints is one field in the request.

How do we avoid printing twice when Shopify re-delivers a webhook?

Shopify retries webhooks, so build your Idempotency-Key from the order or fulfillment ID. A repeated webhook then returns the original job instead of printing a second slip.

Try it on one order

Wire one webhook to one printer.

Install the Station app at a bench, create a key, and print the next order that comes in.

Start printing Download the Station app