Design and print labels on Marklife P15, P12, P7 and other Bluetooth thermal printers

Visual label editor in the browser, powerful CLI for automation and AI agents, and a platform-agnostic TypeScript core.
No server required — everything runs locally via Web Bluetooth or Noble.

🌐 Web Editor • Features • Packages • Quick Start • Printers • Architecture

Web Editor — try it now

• Drag & drop label designer with text, images, QR codes, barcodes, and shapes
• Resize, rotate, and align elements visually on a Konva.js canvas
• Live-preview with gap/continuous paper simulation and ghost labels
• Print directly from the browser via Web Bluetooth (Chrome/Edge)
• Save & load templates, dark mode, responsive layout

CLI

• Discover nearby printers over Bluetooth
• Print images and labels from the terminal
• Check battery and printer status
• Configure label size, density, dithering

Core Library

• Platform-agnostic — inject any BleTransport (Noble, Web Bluetooth, etc.)
• Full image pipeline: RGBA → grayscale → Floyd-Steinberg dither → 1-bit raster
• Credit-based flow control prevents printer buffer overflow
• Device profiles for easy printer support

thermoprint/
  packages/
    core/     @thermoprint/core  — protocol, image pipeline, device profiles
    cli/      @thermoprint/cli   — command-line interface (Noble + sharp)
    web/      @thermoprint/web   — visual label editor (React + Konva.js)

Open tomladder.github.io/thermoprint in Chrome or Edge, connect your printer via Bluetooth, design a label, and print.

# Clone & install
git clone https://github.com/tomLadder/thermoprint.git && cd thermoprint
bun install

# Discover printers (requires Bluetooth)
bun run packages/cli/src/index.ts discover

# Print an image
bun run packages/cli/src/index.ts print my-label.png

Pre-built binaries for macOS, Linux, and Windows are available on the Releases page.

# macOS / Linux
thermoprint discover
thermoprint print label.png

# Check status
thermoprint status

Works out of the box with these Bluetooth thermal label printers:

Have a different printer? Any label printer using the L11 protocol should work. Adding a new printer is just a device profile — a plain object with BLE service/characteristic UUIDs and settings.

┌─────────────────────────────────────────────────────────┐
│            Web Editor (React + Konva.js)                │
│   Toolbar → Canvas → Export → Print via Web Bluetooth   │
├─────────────────────────────────────────────────────────┤
│              CLI (Commander + Chalk + Ora)               │
├─────────────────────────────────────────────────────────┤
│              Printer Orchestrator (Core)                 │
│         connect · print · events · discovery            │
├──────────┬──────────────┬───────────────────────────────┤
│  Image   │   Protocol   │         Device                │
│ Pipeline │    (L11)     │        Registry               │
├──────────┴──────────────┴───────────────────────────────┤
│              FlowController                             │
│         Credit-based BLE chunking                       │
├─────────────────────────────────────────────────────────┤
│         BleTransport (injected)                         │
│     Noble · Web Bluetooth · custom                      │
└─────────────────────────────────────────────────────────┘

Image pipeline: RGBA → grayscale → Floyd-Steinberg dither → 1-bit pack → raster commands

Flow control: Credit-based backpressure prevents buffer overflow. The host waits for credit grants before sending each chunk.

Protocol: L11 is a binary raster protocol. The printer has no built-in fonts — all content is rendered to a bitmap before sending.

import { Printer, discover } from "@thermoprint/core";

const transport = new MyBleTransport();
const peripheral = await discover(transport, { timeoutMs: 5000 });
const printer = await Printer.connect(transport, peripheral);

await printer.print(myImageData, {
  density: 2,
  paperType: "gap",
  dither: "floyd-steinberg",
});

await printer.disconnect();

# Clone
git clone https://github.com/tomLadder/thermoprint.git && cd thermoprint

# Install dependencies
bun install

# Run the web editor locally
bun run --cwd packages/web dev

# Run CLI commands
bun run packages/cli/src/index.ts --help

• Architecture — design decisions, layer diagram, data flow
• Transport — BleTransport interface and flow control
• Image Pipeline — grayscale, dithering, bit packing
• Adding a Printer — how to add a new device profile
• Reverse Engineering — protocol analysis from the Android app

• Runtime: Bun
• Language: TypeScript (strict, ESNext)
• Web: React 19 + Konva.js + Zustand + Tailwind CSS 4
• BLE: @stoprocent/noble (CLI), Web Bluetooth API (Web)
• Image: sharp (CLI), Canvas API (Web)
• CLI: Commander.js + Chalk + Ora

This project is licensed under the MIT License — see the LICENSE file for details.

_{Made with 🖨️ and TypeScript}