Web (browser)

@thermal-label/labelwriter-web talks to Dymo LabelWriter printers directly from Chrome or Edge via the WebUSB API — no backend, no native drivers. It implements the same PrinterAdapter the Node.js driver does, backed by WebUsbTransport from @thermal-label/transport/web.

Browser support

Browser	Support
Chrome 61+	✅
Edge 79+	✅
Firefox	❌
Safari	❌

WebUSB requires a secure context (HTTPS or localhost) and a user gesture (click / keypress) for the initial pairing prompt.

Install

pnpm add @thermal-label/labelwriter-web

Quick start

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

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

image is RawImageData — build one from ImageData returned by a canvas getImageData() call, or from an <img> drawn to an OffscreenCanvas:

const bmp = await createImageBitmap(file);
const canvas = new OffscreenCanvas(bmp.width, bmp.height);
const ctx = canvas.getContext('2d')!;
ctx.drawImage(bmp, 0, 0);
const id = ctx.getImageData(0, 0, bmp.width, bmp.height);
const image = { width: id.width, height: id.height, data: new Uint8Array(id.data.buffer) };

Connect to a previously paired device

import { fromUSBDevice } from '@thermal-label/labelwriter-web';

const [usbDevice] = await navigator.usb.getDevices();
const printer = await fromUSBDevice(usbDevice);

fromUSBDevice() is async — it hands the device to WebUsbTransport.fromDevice() which opens it and claims interface 0.

Status

const status = await printer.getStatus();

status.ready; // printer idle and error-free
status.mediaLoaded; // label roll present
status.detectedMedia; // LabelWriterMedia | undefined (550 only)
status.errors; // PrinterError[] — same shape as the node driver

On the 550 series, detectedMedia is populated automatically from the 32-byte status response. Subsequent print() calls can omit media and the adapter will reuse the detection.

Preview

const preview = await printer.createPreview(image, {
  media: MEDIA.SHIPPING_STANDARD,
});
preview.planes[0].bitmap; // 1bpp LabelBitmap
preview.planes[0].displayColor; // '#000000' — single-colour driver

For offline previews, import createPreviewOffline from @thermal-label/labelwriter-core.

Live demo

Try it in your browser: Demo

NFC label lock

550 series

The LabelWriter 550 series enforces NFC chip validation on label rolls at the hardware level. Non-certified labels will be rejected. See Getting started — NFC label lock.

API summary

Export	Description
requestPrinter(opts?)	Show the USB picker and wrap the selected device
fromUSBDevice(device)	Wrap a pre-paired USBDevice (async)
WebLabelWriterPrinter	Adapter class
DEFAULT_FILTERS	LabelWriter VID/PID filter set

WebLabelWriterPrinter implements PrinterAdapter from @thermal-label/contracts — print, createPreview, getStatus, close, plus the family, model, device, connected getters and the driver-specific recover() helper.