tsdown.dev

What It Is

tsdown positions itself as “The Elegant Library Bundler.” It is a TypeScript/JavaScript bundler for library development, powered by Rolldown and Oxc. It emphasizes fast builds and declaration file generation, while reducing the configuration burden for library authors through sensible presets. Its goal is not to be a general-purpose application build platform, but rather to focus on publishing scenarios such as npm packages, component libraries, and utility libraries.

Core Capabilities and Ecosystem

Based on the scraped text, tsdown has a fairly complete configuration surface: it supports entry, outDir, clean, deps, watch, target, platform, tree-shaking, source maps, minify, dts, package exports, unbundle, CSS, executable packages, package validation, and more. Output formats include esm, cjs, iife, and umd, making it suitable for publishing multiple module formats at the same time. For declaration files, dts can be enabled manually, and can also be enabled automatically based on the types, typings, or exports type conditions in package.json.

Ecosystem compatibility is one of its major selling points: it supports Rollup, Rolldown, unplugin plugins, and some Vite plugins, and provides recipes for Vue, React, Solid, Svelte, WASM, and more. It is also compatible with tsup’s main options and features. The official FAQ describes it as the spiritual successor to tsup, so migration costs should be relatively manageable.

Pricing and Documentation

The scraped text does not mention any commercial pricing or paid service information, so its business model cannot be confirmed. As a local build tool, it appears more like a free development dependency. The documentation quality is good, covering getting started, migration, FAQ, options, CLI, type definitions, Programmatic Usage, and Benchmark. Each UserConfig field includes its type, default value, and explanation. It also provides /llms.txt and Markdown documentation entry points, making it friendly to AI and automated retrieval workflows.

Pros and Cons

Its advantages are that many common library-bundling capabilities are built in, with friendly default configuration; it has broad plugin ecosystem support and makes migration from tsup convenient; it also supports monorepo workspaces, package validation, publint, arethetypeswrong, and other pre-publish checks. The limitations are that several features are still marked experimental, such as CSS, DevTools, Executable, and Workspace. The official documentation also clearly states that stub mode is not supported, and recommends alternatives such as watch mode, exports.devExports, vite-node, tsx, and jiti. In addition, the scraped text does not specify the license, maintenance team, community size, or long-term stability.

Who It’s For and Access from China

It is suitable for TypeScript library authors, npm package maintainers, monorepo teams, and developers who want to migrate from tsup to the Rolldown ecosystem. If a project relies heavily on esbuild-specific behavior, plugin compatibility and output differences should be verified before migration. Regarding access from China, the text does not provide information about network availability, mirrors, or payments, so this remains unknown. In practice, usage mainly depends on npm package registries and GitHub documentation, so configuring a domestic npm mirror may be worth considering. Alternatives include tsup, Rollup, Vite library mode, unbuild, and esbuild.