# robertkrimen/otto

A JavaScript interpreter in Go (golang)

Repository: https://github.com/robertkrimen/otto
Canonical: https://ross.abutalabs.com/products/otto
Homepage: http://godoc.org/github.com/robertkrimen/otto
Language: Go
License: MIT
License Family: permissive
Last push: 2025-06-13T16:08:31+00:00

## Health v2 (maintenance only)
Score: 46/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 26, release rhythm 40, longevity 100
- inputs: {"age_days": 5080, "days_push": 446, "days_rel": 666, "gap_med": 0, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8452, forks 600 (observed 2026-08-28T04:10:21.238802+00:00)

## What it is
Otto is a JavaScript parser and interpreter written natively in Go, providing an embeddable VM for running JavaScript inside Go applications. It includes a separate parser package for building ASTs and a CLI for running JavaScript from the command line.

## Use cases
- run javascript inside a go application
- embed a scripting engine in my go program
- parse javascript into an ast in go
- evaluate user-supplied javascript expressions safely in go
- call go functions from javascript
- execute javascript from the command line

## When to choose
- you need to embed a lightweight JavaScript runtime in a Go application without cgo or external dependencies
- you want to parse JavaScript source into an AST from Go
- you need a simple sandboxed VM for evaluating expressions or user scripts

## When to avoid
- you need full modern ECMAScript (ES6+) compliance or high performance - use goja or a V8 binding instead
- you need Node.js APIs, modules, or the browser DOM
- you need a production-grade, spec-complete JavaScript engine

## Facets
- artifact type: library
- maturity: active
- function: interpreter, parser, developer-tools
- domain: programming-languages, parsers, developer-tools
- platform: go, cross-platform, cli
- tags: javascript-engine, ecmascript, vm, embedding, scripting

## Member repositories
- robertkrimen/otto (main) score 46

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:21.238802+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 2026-08-29T17:27:12.685600+00:00, confidence not recorded.
  - readme: https://github.com/robertkrimen/otto (fetched 2026-08-28T04:10:21.238802+00:00, sha 83ef9937a139)
  - homepage: http://godoc.org/github.com/robertkrimen/otto (fetched 2026-08-29T08:27:02.733080+00:00, sha 2d7b59ae90ad)
  - site_page: https://pkg.go.dev/about (fetched 2026-08-29T08:27:02.740128+00:00, sha 757852027879)
  - site_page: https://pkg.go.dev/github.com/robertkrimen/otto (fetched 2026-08-29T08:27:02.736937+00:00, sha 390853475a56)
  - site_page: https://go.dev/project (fetched 2026-08-29T08:27:02.742600+00:00, sha d5ca00bb378b)
- Data as of 2026-08-30T08:39:29.467469+00:00.