Local Build and Testing npm run build From the root of this local @stencil/core repo, run npm link From the root of a local stencil app, run npm link @stencil/core Every time you run npm run build your linked projects will have to restart the dev server. Test test test. Add unit tests for any updates and always run npm run test. Release npm run release.prepare Check the changelog and make sure it is good, then commit the changes. npm run release 🎉