Mikro.js

TypeScript-first runtime for microcontrollers with a focus on developer experience and iteration speed.

Documentation · Getting Started · API Reference · Examples

Note

Mikro.js is in early development. Expect APIs to change.

Features

• Fast feedback loop: save a file and the device runs the new code seconds later
• Full TypeScript: near-complete ES2024, type-checked hardware APIs, editor autocomplete
• Batteries included: GPIO, PWM, I2C, SPI, UART, WiFi, HTTP, UDP, NeoPixel, deep sleep, SNTP, CBOR, schema validation, key-value storage
• Host simulator: run your code on your computer with mikro sim dev, no microcontroller attached
• No exceptions: typed Result errors instead of try/catch, so every expected failure is visible in the signature
• Built-in testing: test suites with resource leak detection, in the simulator or on real hardware

Quickstart

npm create mikro

Example

import {DigitalOut} from 'mikro/gpio'
import {sleep} from 'mikro/sleep'

const led = DigitalOut(20).orPanic('Failed to configure LED pin')

while (true) {
  led.write(1)
  await sleep(500)
  led.write(0)
  await sleep(500)
}

Overview

The core runtime is a standalone C++ library with no ESP-IDF dependencies. This makes it portable across platforms.

• Engine: QuickJS-NG (near-complete ES2024 coverage)
• Runtime: Standalone C++ library with cooperative, single-threaded event loop
• Platform: ESP-IDF >= 6.1 (ESP32, ESP32-C3, ESP32-S3, ESP32-C5, ESP32-C6), desktop (macOS, Linux)
• Modules: Four-source resolution: virtual modules, native C modules, bytecode builtins, filesystem (LittleFS)
• Bytecode: TypeScript bundled with esbuild, compiled to QuickJS bytecode at build time
• Tooling: Node.js CLI (Ink/React), Node-API addon for host-side development and simulation

Acknowledgements

Mikro.js has drawn heavy inspiration from txiki.js, a small JavaScript runtime built on QuickJS.

Thanks to Felix Wieland (@flexwie) for generously donating the mikro package name on npm.

License

MIT