# esm-dev/esm.sh

A no-build JavaScript CDN for modern web development.

Repository: https://github.com/esm-dev/esm.sh
Canonical: https://ross.abutalabs.com/products/esmsh
Homepage: https://esm.sh
Language: Go
License: MIT
License Family: permissive
Topics: esm, nobuild, cdn, web-development
Last push: 2026-08-24T14:44:43+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 99, longevity 100
- inputs: {"age_days": 2187, "days_push": 9, "days_rel": 9, "gap_med": 20, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4158, forks 206 (observed 2026-08-28T04:08:37.344058+00:00)

## What it is
esm.sh is a no-build JavaScript CDN that serves npm, JSR, and GitHub packages as ES modules over HTTP URLs, transforming TypeScript, Vue, and Svelte files on the fly. It is written in Go and can be self-hosted, letting modern web apps import dependencies directly in the browser or Deno without bundlers or install steps.

## Use cases
- import npm packages directly in the browser without a bundler
- serve ES modules from a CDN for a no-build web app
- use import maps with bare specifiers like react
- transform tsx, vue, and svelte files on the fly in the browser
- import packages from GitHub repos or JSR by URL
- prototype web apps in Deno using npm packages
- self-host an ESM CDN for internal packages

## When to choose
- you want zero build tooling and to load dependencies straight from URLs
- you are building quick prototypes, demos, or Deno scripts using npm packages
- you need on-the-fly transformation of TypeScript, Vue, or Svelte in the browser
- you want to pin package versions or submodules via simple URL patterns

## When to avoid
- you need a full production build pipeline with tree-shaking, minification, and code splitting
- your app must work offline or in environments without CDN access
- you require strict supply-chain control over every dependency and its transitive graph

## Facets
- artifact type: service
- maturity: active
- function: http-server, developer-tools, web-framework
- domain: web-development, frontend, developer-tools, apis
- platform: self-hosted, go
- tags: cdn, esm, no-build, npm-packages, import-maps, deno, browser-modules, web-server

## Member repositories
- esm-dev/esm.sh (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:37.344058+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 2026-08-29T18:22:50.717557+00:00, confidence not recorded.
  - readme: https://github.com/esm-dev/esm.sh (fetched 2026-08-28T04:08:37.344058+00:00, sha 3c179bf18098)
  - homepage: https://esm.sh (fetched 2026-08-29T09:13:35.219114+00:00, sha d4f70bf630d9)
- Data as of 2026-08-30T08:39:29.467469+00:00.