Getting started

Node.js

Install

pnpm add @thermal-label/labelwriter-node

Print over USB

import { discovery } from '@thermal-label/labelwriter-node';
import { MEDIA } from '@thermal-label/labelwriter-core';

const printer = await discovery.openPrinter();
try {
  // image is `RawImageData` — `{ width, height, data }` where `data` is a
  // `Uint8Array` of RGBA pixels. Produce it from @napi-rs/canvas, sharp,
  // or any server-side image pipeline.
  await printer.print(image, MEDIA.ADDRESS_STANDARD);
} finally {
  await printer.close();
}

Print over TCP (network-attached models)

import { discovery } from '@thermal-label/labelwriter-node';
import { MEDIA } from '@thermal-label/labelwriter-core';

const printer = await discovery.openPrinter({ host: '192.168.1.100' });
try {
  await printer.print(image, MEDIA.SHIPPING_STANDARD, { density: 'high' });
} finally {
  await printer.close();
}

Linux udev rule

USB access on Linux requires a udev rule. Create /etc/udev/rules.d/99-labelwriter.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="0922", GROUP="plugdev", MODE="0664"

Then reload rules and add your user to the plugdev group:

sudo udevadm control --reload-rules
sudo usermod -aG plugdev $USER

Log out and back in for the group change to take effect.

Unified CLI

For ad-hoc printing from a terminal, use thermal-label-cli. It auto-detects every installed @thermal-label/*-node driver:

pnpm add -g thermal-label-cli @thermal-label/labelwriter-node
thermal-label list
thermal-label print ./label.png --media address-standard

Web (browser)

Install

pnpm add @thermal-label/labelwriter-web

Requires Chrome or Edge (WebUSB is not supported in Firefox or Safari), served from a secure context (https:// or localhost).

Quick start

import { requestPrinter } from '@thermal-label/labelwriter-web';
import { MEDIA } from '@thermal-label/labelwriter-core';

// Must run from a user gesture (click handler, etc.)
const printer = await requestPrinter();
try {
  await printer.print(image, MEDIA.ADDRESS_STANDARD);
} finally {
  await printer.close();
}

NFC label lock

What is it?

The Dymo LabelWriter 550 series (550, 550 Turbo, 5XL, and related models) includes hardware-level NFC validation. Before printing, the printer reads an NFC chip embedded in the label roll. If the chip is absent or not recognised as a genuine Dymo label, the printer reports a paper-out error and refuses to print.

Which models are affected?

All protocol: '550' devices — see Hardware for the full list. The 450 series and older models do not have this restriction.

Can it be bypassed?

No. The NFC check is performed entirely within the printer's own firmware, independent of the host software. There is no command or sequence that disables it. Using genuine Dymo-certified label rolls is the only solution.

What does the error look like?

getStatus() returns a PrinterStatus whose errors[] contains a { code: 'no_media', message: 'No labels loaded' } entry and whose ready is false. The printer also shows a blinking orange LED.