tsdown is a next-generation TypeScript library bundler built on Rolldown and Oxc. It provides blazing-fast builds, automatic .d.ts generation, and seamless migration from tsup. Supports Rolldown/Rollup/Unplugin plugins and features smart dependency handling.

The skill is based on tsdown v0.20.1, generated at 2026-01-28.

Anthony's Preferences:

Build pure-ESM packages, avoid CJS
Always enable dts option for type declarations
Enable exports option for auto-generated package exports

Core

Topic	Description	Reference
Configuration	Config file setup, defineConfig, multiple configs	core-config
CLI	Command-line interface and options	core-cli
Entry Points	Entry files, aliases, glob patterns	core-entry

tsdown

Core

Build Options