# rolldown/tsdown

The elegant bundler for libraries powered by Rolldown

Repository: https://github.com/rolldown/tsdown
Canonical: https://ross.abutalabs.com/products/tsdown
Homepage: https://tsdown.dev
Language: TypeScript
License: MIT
License Family: permissive
Topics: library, oxc, rolldown, typescript, bundler
Last push: 2026-08-25T19:52:50+00:00

## Health v2 (maintenance only)
Score: 86/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 99, release rhythm 82, longevity 64
- inputs: {"age_days": 908, "days_push": 8, "days_rel": 41, "gap_med": 2.0, "n_releases_24m": 153}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4233, forks 184 (observed 2026-08-28T04:08:39.485238+00:00)

## What it is
tsdown is a fast bundler designed for building JavaScript/TypeScript libraries, powered by Rolldown and Oxc. It generates declaration files, supports Rollup/unplugin/Vite plugin ecosystems, and offers a seamless migration path from tsup.

## Use cases
- bundle a typescript library for npm
- generate d.ts declaration files during build
- migrate from tsup to a faster bundler
- build an npm package with esm and cjs output
- use rollup or vite plugins in a library build
- watch mode for library development

## When to choose
- you are publishing a TypeScript/JavaScript library to npm and want fast builds with declaration output
- you want a batteries-included, preconfigured bundler with minimal setup
- you are on tsup and want a compatible, faster alternative
- you need compatibility with the Rollup/unplugin/Vite plugin ecosystem

## When to avoid
- you are bundling a full web application rather than a library - use Vite or a framework bundler instead
- you rely on tsup's stub mode, which tsdown does not support
- you need a bundler outside the Rolldown/Rollup plugin ecosystem

## Facets
- artifact type: cli-tool
- maturity: active
- function: build-tool, compiler, cli, developer-tools
- domain: developer-tools, web-development, frontend
- platform: cli, cross-platform
- tags: bundler, typescript, rolldown, oxc, library-packaging, declaration-files, tsup-alternative, dts-generation, javascript-ecosystem, nodejs

## Member repositories
- rolldown/tsdown (main) score 86

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:39.485238+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 2026-08-29T18:22:19.766010+00:00, confidence not recorded.
  - readme: https://github.com/rolldown/tsdown (fetched 2026-08-28T04:08:39.485238+00:00, sha 65af8acb8cea)
  - homepage: https://tsdown.dev (fetched 2026-08-29T09:12:30.547158+00:00, sha d6dd88f9ebf8)
  - site_page: https://tsdown.dev/guide/faq (fetched 2026-08-29T09:12:30.549618+00:00, sha 9f3040bc1334)
- Data as of 2026-08-30T08:39:29.467469+00:00.