You will have the best possible developer experience with this starter kit when using VSCode with the suggested extensions.
Once you cloned the project and opened it in VSCode you should be promted to install suggested extensions automatically. In case you rather want to install them manually you can do so at any time later.
These are the extension we recommend:
MJML (opens in a new tab)
Provides tooling to preview the mjml templates and generate the html files from it.
i18n-ally (opens in a new tab)
Enables you to translate your app easily within your editor and gives you previews of the translated strings within your component files.
Prettier (opens in a new tab)
The formatter for the code.
ESLint (opens in a new tab)
Helps writing code that is readable and easy to debug.
The starter kit also comes with some workspace settings for VSCode that make the development flow more seamless. If you want to change then you can do so in the .vscode/settings.json