> For the complete documentation index, see [llms.txt](https://shopify-1.gitbook.io/react/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://shopify-1.gitbook.io/react/3.-advanced-topics/performance-optimizations/development-vs-production-build.md).

# Development vs Production build

This one might seem pretty obvious, but do make sure you’re using the production build of React.

By default, React includes many helpful warnings. These warnings are very useful in development. However, they make React larger and slower so you should make sure to use the production version when you deploy the app.

If you aren’t sure whether your build process is set up correctly, you can check it by installing [React Developer Tools for Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi).

For more details on how to enable the production build, take a look at: <https://reactjs.org/docs/optimizing-performance.html#use-the-production-build>