2023 Year in Review

The arrival of 2024 is an opportunity to reflect on the amazing progress we made in 2023. Our mission has always been to bring the benefits of standard, modern JavaScript to embedded developers. Our work over the past year highlights our wide-ranging efforts in support of that mission.


At Moddable, we believe in adopting industry standards whenever practical to provide interoperability, minimize what developers need to learn, and build on proven designs.

This year we delivered support for ECMAScript 2023 in Moddable SDK 3.9.1. This is the latest JavaScript standard, empowering embedded developers to use the very latest JavaScript features. We made many improvements to JavaScript language conformance to ensure that even subtle edge cases of JavaScript are the same in embedded devices as they are on the web.

We also worked with the Ecma TC53 standards committee to complete the 2nd Edition of ECMA-419, the ECMAScript embedded systems API specification. This suite of standard JavaScript APIs designed for resource-constrained embedded systems is quickly becoming our foundation for IO, sensors, networking, and more.


Developers spend a great deal of time debugging. To help developers make the most of their debugging sessions, we invested in significant enhancements to our JavaScript debugging developer experience. These capabilities may be familiar to web developers but are very unusual in embedded systems.

  • Conditional breakpoints– trigger a breakpoint only on certain conditions, including evaluation of JavaScript expressions and number of times a breakpoint is encountered.

  • Function breakpoints – set a single breakpoint to triggers on all functions of a given name (e.g. onReadable).

  • Tracepoints – a kind of breakpoint that traces to the console instead of stopping. Convenient for generating operational traces without rebuilding.

  • Interactive debugger console (REPL) – This is a way to evaluate JavaScript expressions and call functions when stopped in the debugger. A powerful tool for diagnosing issues and even experimenting with solutions.

Our interactive performance profiler is indispensable for developers who need to pinpoint performance hotspots in their embedded JavaScript. This year we extended the profiler to work with our popular mods feature, making the profiler available in more situations.


This year we introduced support for Nordic's nRF52, a popular low-energy microcontroller. To go along with that, we launched Moddable Four, a coin-cell powered development board built around the nRF52. Moddable Four is the easiest way for JavaScript developers to get started with ultra low-energy development.

Many developers use the Moddable SDK with the ESP32 family of microcontrollers from Espressif. Here are a few of the advances in ESP32 support:

  • ESP-IDF v5 is now the default thanks to a huge, community supported effort. This ensures developers have access to the latest features and fixes from Espressif.

  • ESP32-H2 and ESP32-C6 microcontroller support

  • PSRAM enabled to significantly increase RAM available to projects

  • Built-in Ethernet is now supported so you can connect to Ethernet without a separate Ethernet controller

Support continues to grow for a wide range of development boards across all supported microcontroller platforms. There's too many to list here so check out the supported device lists for ESP32, Raspberry Pi Pico, and nRF52.


In 2023 we once again had the opportunity to talk with developers of embedded systems in person at several events. We always learn so much from the questions and reactions as we share the benefits of industry-standard embedded JavaScript.

  • FOSDEM – Held each year in Brussels, FOSDEM is a leading open source community event. Moddable demonstrated the power of embedded JavaScript to developers who were surprised at how much was possible.

  • Sensors Converge – Moddable exhibited at this major industry embedded development conference to talk about standardization and sensors. Attendees recognized that JavaScript could solve many of the challenges they face in embedded software development.

  • Ecma TC53 Workshop – This workshop on the future of embedded JavaScript brought together experts from industry and the open source community for a day of collaborative, wide-ranging discussion.

Community Projects

Every year the Moddable team supports a variety of open source projects built around the Moddable SDK. Here are some from 2023:

  • xs-devThis command line tool automates many common Moddable SDK tasks including installing, updating, and creating new projects. For most developers, xs-dev has become the best way to get started with the Moddable SDK.

  • Stack-chan - This award-winning personal companion robot from Japan remains one of our favorites. To celebrate its second birthday, we surprised the Stack-chan community with MP3 streaming support and Text-to-Speech using ElevenLabs.io -- all so that Stack-chan's ChatGPT integration can more easily talk.

  • Node-RED MCU Edition - This embedded version of the popular Node-RED low-code development environment continues to grow with support for new sensors, real-time clock integration, a major update to IO capabilities, and integration with the Node-RED Library.

And So Much More

2023 was a busy year, so we can't possible cover everything here. Fortunately, there are a few easy ways for you to catch-up on 2023 and keep us with us in 2024:

  • Monthly releases. Each month we publish a release of the Moddable SDK with detailed release notes on.

  • Blog. Our blog features articles on news and new features.

  • Twitter / X - An easy way to keep up to date on the latest news from Moddable and the embedded JavaScript ecosystem.

As always, thank you to our entire community. Your contributions, bug reports, questions, and words of encouragement are what power the Moddable ecosystem. We're excited to see what 2024 will bring.