@swc/cli is the command-line interface for the Speedy Web Compiler (SWC), a platform for next-generation fast developer tools. It allows you to use SWC directly from your terminal for tasks like compiling TypeScript and JavaScript code, bundling, and transforming code with configurable options through .swcrc files. It offers significant speed improvements over traditional tools like Babel, making it ideal for large projects or Continuous Integration/Continuous Deployment environments.