A runtime for TypeScript or JavaScript programs that is positioned as a single-executable alternative to TypeScript + Babel + Node + NPM + ESLint + Prettier + Webpack. Modules are imported from URLs (same system as ES6 modules running in browsers), and asynchronous APIs use promises rather than those old-fashioned callbacks (so not a drop-in replacement for Node). Implemented in Rust, and aiming to be secure-by-default by restricting access to files and networks unless explicitly allowed.