# just-js/just

the only javascript runtime to hit no.1 on techempower :fire:

Repository: https://github.com/just-js/just
Canonical: https://ross.abutalabs.com/products/just-js-just
Homepage: https://just.billywhizz.io/
Language: JavaScript
License: MIT
License Family: permissive
Topics: javascript, linux, runtime, system-programming
Last push: 2023-11-17T12:28:54+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 2238, "days_push": 1020, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3808, forks 123 (observed 2026-08-28T04:08:20.488250+00:00)

## What it is
Just is a very small JavaScript runtime for Linux built directly on V8 and system calls, designed for writing system software with near-native performance. It reached #1 on TechEmpower benchmarks and doubles as a teaching platform for Linux system programming and V8 internals.

## Use cases
- run javascript scripts on linux with minimal overhead
- build high-performance http servers in javascript
- learn linux system programming and v8 internals
- write system software in javascript without node.js
- benchmark a javascript runtime against native frameworks

## When to choose
- you need a tiny, hackable JS runtime on linux with minimal dependencies
- you want maximum raw performance for javascript http workloads
- you want to learn how runtimes and v8 work internally

## When to avoid
- you need cross-platform support (linux x86_64 only)
- you need ES modules or a rich standard library
- you need an actively maintained project (development moved to just-js/lo)

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: http-server, cli, developer-tools
- domain: programming-languages, developer-tools, performance
- platform: cli
- tags: javascript-runtime, v8, system-programming, techempower, low-level, command-line, linux, javascript

## Member repositories
- just-js/just (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:20.488250+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 2026-08-29T18:26:45.841447+00:00, confidence not recorded.
  - readme: https://github.com/just-js/just (fetched 2026-08-28T04:08:20.488250+00:00, sha fb476d276a09)
  - homepage: https://just.billywhizz.io/ (fetched 2026-08-29T09:21:45.369126+00:00, sha fe1f36dd0a47)
- Data as of 2026-08-30T08:39:29.467469+00:00.