# Hans-Halverson/brimstone

New JavaScript engine written in Rust

Repository: https://github.com/Hans-Halverson/brimstone
Canonical: https://ross.abutalabs.com/products/brimstone
Language: Rust
License: MIT
License Family: permissive
Topics: ecmascript, javascript, javascript-engine, runtime, vm, compiler, interpreter
Last push: 2026-08-23T17:06:21+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 35, longevity 98
- inputs: {"age_days": 1384, "days_push": 10, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1317, forks 32 (observed 2026-08-28T04:04:21.041371+00:00)

## What it is
Brimstone is a JavaScript engine written from scratch in Rust, implementing nearly the full ECMAScript specification (ES2026) including a bytecode VM, compacting garbage collector, custom parser, and RegExp engine. It is a work in progress with >97% test262 conformance and is not yet production-ready.

## Use cases
- run javascript files from the command line
- embed a javascript engine in a rust application
- study how a javascript engine is implemented
- test ecmascript conformance against test262
- experiment with bytecode vm and garbage collector design in rust

## When to choose
- you need a self-contained, minimal-dependency JS engine in Rust
- you want to hack on or learn from a from-scratch ECMAScript implementation
- you need recent ES2026 features like Temporal in a Rust-native engine

## When to avoid
- you need a production-grade, battle-tested JavaScript runtime
- your code relies on SharedArrayBuffer or Atomics
- you need Node.js APIs or an npm ecosystem runtime

## Facets
- artifact type: library
- maturity: experimental
- function: interpreter, compiler, programming-language, parser, testing, fuzzing
- domain: programming-languages, compilers, parsers, developer-tools, performance
- platform: rust, cross-platform, cli
- tags: javascript-engine, ecmascript, bytecode-vm, garbage-collector, test262, v8-inspired

## Member repositories
- Hans-Halverson/brimstone (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:21.041371+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 2026-08-30T04:48:11.352928+00:00, confidence not recorded.
  - readme: https://github.com/Hans-Halverson/brimstone (fetched 2026-08-28T04:04:21.041371+00:00, sha 79e0fdca7090)
- Data as of 2026-08-30T08:39:29.467469+00:00.