# Moddable-OpenSource/moddable

Tools for developers to create truly open IoT products using standard JavaScript on low cost microcontrollers.

Repository: https://github.com/Moddable-OpenSource/moddable
Canonical: https://ross.abutalabs.com/products/moddable
Homepage: http://www.moddable.com
Language: C
License Family: other
Last push: 2026-08-05T19:53:18+00:00

## Health v2 (maintenance only)
Score: 97/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 96, release rhythm 96, longevity 100
- inputs: {"age_days": 3242, "days_push": 28, "days_rel": 28, "gap_med": 23.0, "n_releases_24m": 33}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1551, forks 277 (observed 2026-08-28T04:05:02.305993+00:00)

## What it is
The Moddable SDK is a development toolkit and runtime for building IoT applications in standard JavaScript on low-cost microcontrollers like ESP32, ESP8266, and nRF52. It centers on the XS JavaScript engine, which implements the ECMAScript standard with high conformance while running in as little as 45 KB of memory.

## Use cases
- build IoT products with JavaScript on microcontrollers
- run JavaScript on ESP32 or ESP8266
- create firmware for constrained embedded devices
- develop touchscreen UIs for smart appliances
- add BLE or MQTT connectivity to embedded hardware
- prototype connected devices without writing C

## When to choose
- you want to use JavaScript instead of proprietary embedded SDKs
- your target microcontroller has very limited RAM and flash
- you need standards-conformant JavaScript on embedded hardware
- you're building consumer or industrial IoT products with displays and networking

## When to avoid
- you need maximum performance or hard real-time guarantees
- your team only knows C/C++ embedded workflows
- you're targeting Linux-class single-board computers rather than microcontrollers
- you require a permissively licensed open-source project (the repo has no license file)

## Facets
- artifact type: framework
- maturity: active
- function: sdk, interpreter, networking, graphics, build-tool, developer-tools
- domain: iot, embedded-systems, programming-languages, developer-tools
- platform: embedded, iot, windows, wasm
- tags: javascript-engine, xs-engine, microcontrollers, embedded-javascript, iot-sdk, ecma-419, ble, mqtt, macos, linux

## Member repositories
- Moddable-OpenSource/moddable (main) score 97

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:02.305993+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:30:14.875589+00:00, confidence not recorded.
  - readme: https://github.com/Moddable-OpenSource/moddable (fetched 2026-08-28T04:05:02.305993+00:00, sha 866584bf5bcd)
  - homepage: http://www.moddable.com (fetched 2026-08-29T11:30:50.731520+00:00, sha 5a1ceb6105e3)
  - site_page: https://www.moddable.com/documentation/readme (fetched 2026-08-29T11:30:50.734142+00:00, sha faf315d09b13)
  - site_page: https://www.moddable.com/blog/guides (fetched 2026-08-29T11:30:50.738213+00:00, sha 9260a609af6d)
  - site_page: https://www.moddable.com/faq (fetched 2026-08-29T11:30:50.736252+00:00, sha 326470b0bf84)
- Data as of 2026-08-30T08:39:29.467469+00:00.