# macaly/almostnode

Node.js in your browser. Just like that.

Repository: https://github.com/macaly/almostnode
Canonical: https://ross.abutalabs.com/products/almostnode
Homepage: http://almostnode.dev/
Language: TypeScript
License: MIT
License Family: permissive
Topics: nodejs, webcontainers
Last push: 2026-02-14T22:28:55+00:00

## Health v2 (maintenance only)
Score: 45/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 67, release rhythm 35, longevity 15
- inputs: {"age_days": 216, "days_push": 200, "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 1160, forks 103 (observed 2026-08-28T04:03:49.002103+00:00)

## What it is
almostnode is a TypeScript library that emulates a Node.js runtime entirely in the browser, providing a POSIX-compatible virtual filesystem, 40+ shimmed Node.js modules, and a client-side npm package manager. It also ships built-in Vite and Next.js dev servers with HMR, exposed through a service worker bridge so virtual servers are reachable via real URLs.

## Use cases
- run node.js code in the browser
- install npm packages client-side without a server
- run express or http servers entirely in the browser
- run vite or next.js dev server in the browser
- sandbox and execute untrusted javascript safely
- build an in-browser coding playground or REPL
- run cli tools like eslint or vitest in the browser

## When to choose
- you need a Node.js-like environment or dev server running fully client-side with no backend
- you're building an online IDE, playground, or AI coding agent that executes code in the browser
- you need to run npm packages or CLI tools (vitest, eslint, tsc) without a server
- you need sandboxed execution of untrusted code via cross-origin isolation

## When to avoid
- you need a production-grade, fully compatible Node.js runtime — this is experimental and emulates only a subset of Node 20 APIs
- your code relies on native modules, real OS filesystem access, or full Node.js fidelity
- you're running trusted code on the main thread with createContainer() — it has no isolation

## Facets
- artifact type: library
- maturity: experimental
- function: http-server, package-manager, file-system, interpreter, developer-tools, sdk
- domain: web-development, developer-tools, frontend
- platform: browser, wasm
- tags: nodejs-runtime, webcontainers, virtual-filesystem, npm-in-browser, in-browser-dev-server, sandboxed-execution, service-worker, hmr, vite, nextjs, javascript, web-server, nodejs

## Member repositories
- macaly/almostnode (main) score 45

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:49.002103+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 2026-08-30T06:31:49.078589+00:00, confidence not recorded.
  - readme: https://github.com/macaly/almostnode (fetched 2026-08-28T04:03:49.002103+00:00, sha 89bcf6351749)
  - homepage: http://almostnode.dev/ (fetched 2026-08-29T12:36:42.557940+00:00, sha 2d93cfac1618)
  - site_page: http://almostnode.dev/docs (fetched 2026-08-29T12:36:42.567149+00:00, sha aa73477d2808)
  - site_page: http://almostnode.dev/docs/security.html (fetched 2026-08-29T12:36:42.570957+00:00, sha a612cf0f8074)
  - site_page: http://almostnode.dev/docs/api-reference.html (fetched 2026-08-29T12:36:42.572931+00:00, sha 174d58bab26e)
  - registry_npm: https://registry.npmjs.org/almostnode (fetched 2026-08-29T12:36:42.574733+00:00, sha ab961f5bbe6f)
  - site_page: http://almostnode.dev/examples/express-demo.html (fetched 2026-08-29T12:36:42.569123+00:00, sha 35fd0d0880b6)
- Data as of 2026-08-30T08:39:29.467469+00:00.