Modern build stack

The modern build stack is two independent tracks. Enable either or both.

1. Meteor Bundler Optimizations (Meteor 3.3+). One flag, SWC replaces Babel, SWC minifier replaces Terser, @parcel/watcher replaces the legacy watcher, development skips legacy archs.
2. Rspack Bundler Integration (Meteor 3.4+). Atmosphere package delegates app-code compilation to Rspack. Tree shaking, ESM, code splitting via HTTP, modern bundler plugins.

Standard current meteor create application skeletons ship both enabled. Purposefully small or compatibility-oriented skeletons, including minimal and legacy, may omit Rspack or the modern flag. Inspect the generated package.json and .meteor/packages instead of inferring features only from the Meteor version. For existing apps, enable optimizations first, then add Rspack once the app code is standards-clean.

Enable Meteor Bundler Optimizations