# cesanta/elk

A low footprint JavaScript engine for embedded systems

Repository: https://github.com/cesanta/elk
Canonical: https://ross.abutalabs.com/products/cesanta-elk
Language: C
License: NOASSERTION
License Family: other
Topics: js, javascript, engine, embedded, tiny, small, javascript-engine
Last push: 2026-03-18T17:59:48+00:00

## Health v2 (maintenance only)
Score: 55/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 72, release rhythm 8, longevity 100
- inputs: {"age_days": 2522, "days_push": 168, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- 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 1900, forks 98 (observed 2026-08-28T04:05:51.337415+00:00)

## What it is
Elk is a tiny embeddable JavaScript engine written in C that implements a small subset of ES6, designed for microcontrollers with footprints around 20KB flash and ~100 bytes RAM. It has no standard library; JS code orchestrates functionality imported from C/C++ firmware.

## Use cases
- run JavaScript on an Arduino or ESP32 microcontroller
- let customers customise device firmware with small JS scripts
- embed a scripting engine in a C project without malloc
- add JS customisation hooks to embedded firmware
- evaluate simple JS expressions in a memory-constrained environment

## When to choose
- you need a minimal JS interpreter on 8/32-bit microcontrollers with very little RAM
- you want to expose C functions to user-written JS scripts
- you need zero dependencies and a copy-two-files integration

## When to avoid
- you need a full ES6+ runtime or standard library
- you need high-performance JIT execution
- you need a general-purpose server-side JS environment like Node.js

## Facets
- artifact type: library
- maturity: active
- function: interpreter, programming-language, embedded
- domain: programming-languages, embedded-systems, developer-tools
- platform: embedded, cross-platform, c, cpp
- tags: javascript-engine, microcontroller, es6-subset, no-malloc, tiny-footprint, scripting

## Member repositories
- cesanta/elk (main) score 55

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:51.337415+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 2026-08-30T03:11:58.818808+00:00, confidence not recorded.
  - readme: https://github.com/cesanta/elk (fetched 2026-08-28T04:05:51.337415+00:00, sha 8e1d472ee453)
- Data as of 2026-08-30T08:39:29.467469+00:00.