tsdown

Spec sheet

Purpose

tsdown is a bundler designed for building TypeScript and JavaScript libraries.Read 7 Oct 2026 · tsdown.dev

Intended users

The documentation describes tsdown as a tool for library authors, from small utilities to complex libraries.Read 7 Oct 2026 · tsdown.dev

Integrations

The project says it supports Rolldown, Unplugin, and most Rollup plugins, as well as some Vite plugins.Read 7 Oct 2026 · tsdown.dev

License

The project website states that tsdown is released under the MIT License.Read 7 Oct 2026 · tsdown.dev

Maker

The project credits VoidZero Inc. and contributors.Read 7 Oct 2026 · tsdown.dev

Assets

It can include and process non-code assets such as JSON and WASM files.Read 7 Oct 2026 · tsdown.dev

Assets and optimization

It supports JSON and WASM assets, tree shaking, minification, and source maps.Read 7 Oct 2026 · tsdown.dev

Build engine

tsdown is built on Rolldown, a Rust-based bundler.Read 7 Oct 2026 · tsdown.dev

Build outputs

It can produce ESM, CJS, IIFE, and UMD bundles, along with TypeScript declaration files.Read 7 Oct 2026 · tsdown.dev

Bundler engine

tsdown is powered by Rolldown, a Rust-based bundler.Read 7 Oct 2026 · tsdown.dev

Configuration

tsdown reads package.json and tsconfig.json to infer defaults, including dependency externalization and some declaration generation settings.Read 7 Oct 2026 · tsdown.dev

Declarations

tsdown can automatically generate TypeScript declaration files for libraries.Read 7 Oct 2026 · tsdown.dev

Experimental executable feature

Executable bundling is experimental, requires Node.js >=25.7.0, and is not supported in Bun or Deno.Read 7 Oct 2026 · tsdown.dev

Install

The guide provides installation commands for npm, pnpm, Yarn, and Bun.Read 7 Oct 2026 · tsdown.dev

Installation

The getting-started guide documents installation through npm, pnpm, yarn, and Bun.Read 7 Oct 2026 · tsdown.dev

Migration

The homepage says tsdown is compatible with tsup's main options and features to support migration.Read 7 Oct 2026 · tsdown.dev

Monorepos

It has workspace mode for detecting monorepo packages and inheriting root configuration.Read 7 Oct 2026 · tsdown.dev

Optimization

Built-in production features include tree-shaking, minification, and source maps.Read 7 Oct 2026 · tsdown.dev

Output formats

It supports ESM, CJS, IIFE, and UMD output formats.Read 7 Oct 2026 · tsdown.dev

Plugins

It supports Rolldown plugins, most Rollup plugins, and many Unplugin plugins; some Rollup plugins may cause TypeScript type errors.Read 7 Oct 2026 · tsdown.dev

Runtime requirement

The guide requires Node.js ^22.18.0, ^24.11.0, or >=26.0.0 to run tsdown and says Bun and Deno support is experimental.Read 7 Oct 2026 · tsdown.dev

Security and compliance

The opened tsdown pages did not state security certifications or compliance claims.Read 7 Oct 2026 · tsdown.dev

Try online

The getting-started guide offers an online StackBlitz template for trying tsdown in a browser without local setup.Read 7 Oct 2026 · tsdown.dev

Where Specifiction places it

• JavaScript Build Tools#27 of 277.0